Light receiving element and electronic apparatus

ABSTRACT

A first light receiving element according to an embodiment of the present disclosure includes a plurality of pixels, a photoelectric converter that is provided as a layer common to the plurality of pixels, and contains a compound semiconductor material, and a first electrode layer that is provided between the plurality of pixels on light incident surface side of the photoelectric converter, and has a light-shielding property.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a national stage application under 35 U.S.C. 371 andclaims the benefit of PCT Application No. PCT/JP2018/045704 having aninternational filing date of 12 Dec. 2018, which designated the UnitedStates, which PCT application claimed the benefit of Japanese PatentApplication No. 2017-253637 filed 28 Dec. 2017, the entire disclosuresof each of which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a light receiving element to be used,for example, for an infrared sensor or the like, and an electronicapparatus including the same.

BACKGROUND ART

In recent years, as an image sensor (infrared sensor) having sensitivityto an infrared region, a semiconductor element (light receiving element)in which a photoelectric conversion layer is formed using a compoundsemiconductor has been developed. In the image sensor using thesemiconductor element, similarly to a light receiving element using Si,in a case where a light-shielding film is not disposed between pixels,leakage of light from an adjacent pixel region occurs and color mixtureoccurs.

In contrast, for example, PTL 1 discloses a photoelectric conversiondevice in which a transparent electrode layer is provided over aphotoelectric conversion layer using a compound semiconductor, and alight-shielding film is disposed over an upper layer thereof.

CITATION LIST Patent Literature

PTL 1: Japanese Unexamined Patent Application Publication No. 2014-60380

SUMMARY OF THE INVENTION

Incidentally, in the infrared sensor using such a light receivingelement, it has been desired to improve sensitivity.

It is desirable to provide a light receiving element and an electronicapparatus that make it possible to improve sensitivity.

A first light receiving element according to an embodiment of thepresent disclosure includes a plurality of pixels, a photoelectricconverter that is provided as a layer common to the plurality of pixels,and contains a compound semiconductor material, and a first electrodelayer that is provided between the plurality of pixels on light incidentsurface side of the photoelectric converter, and has a light-shieldingproperty.

A first electronic apparatus according to an embodiment of the presentdisclosure includes the above-mentioned first light receiving elementaccording to an embodiment of the present disclosure.

A second light receiving element according to an embodiment of thepresent disclosure includes a plurality of pixels, a photoelectricconverter that includes a compound semiconductor material, is providedas a layer common to the plurality of pixels, and has a stackedstructure in which a photoelectric conversion layer, a first contactlayer, and a second contact layer are stacked, the photoelectricconversion layer being provided between the first contact layer and thesecond contact layer, an insulating layer provided over thephotoelectric converter, and a transparent electrode layer provided overthe insulating layer.

A second electronic apparatus according to an embodiment of the presentdisclosure includes the above-mentioned second light receiving elementaccording to an embodiment of the present disclosure.

In the first light receiving element and the first electronic apparatusaccording to the respective embodiments of the present disclosure, thefirst electrode layer having a light-shielding property is providedbetween the plurality of pixels on the light incident surface side ofthe photoelectric converter. This eliminates the necessity of forming atransparent electrode over the photoelectric converter. In the secondlight receiving element and the second electronic apparatus according tothe respective embodiments of the present disclosure, the insulatinglayer and the transparent electrode layer are stacked in this order overthe photoelectric converter having a stacked structure in which thefirst contact layer, the second contact layer, and the photoelectricconversion layer are stacked, the photoelectric conversion layer beingprovided between the first contact layer and the second contact layer.Thus, it is possible to reduce a thickness of the first contact layer.

According to the first light receiving element and the first electronicapparatus of the respective embodiments of the present disclosure, sincethe first electrode layer having a light-shielding property is providedbetween the plurality of pixels on the light incident surface side ofthe photoelectric converter, it is not necessary to form a transparentelectrode over the photoelectric converter. According to the secondlight receiving element and the second electronic apparatus of therespective embodiments of the present disclosure, since the transparentelectrode is formed over the photoelectric converter via the insulatinglayer, it is possible to reduce a thickness of the first contact layerprovided on the light incident surface side of the photoelectricconverter. Thus, it is possible for the first light receiving elementand the first electronic apparatus according to the respectiveembodiments of the present disclosure and the second light receivingelement and the second electronic apparatus according to the respectiveembodiments of the present disclosure to improve sensitivity.

It is to be noted that the above description refers to examples of thepresent disclosure. Effects of the present disclosure are not limited tothose described above, and may be other different effects or may furtherinclude other effects.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a cross-sectional schematic view illustrating a schematicconfiguration of a light receiving element according to a firstembodiment of the present disclosure.

FIG. 2 includes schematic views each illustrating a cross-sectionalshape of an electrode on light incident surface side of the lightreceiving element illustrated in FIG. 1 .

FIG. 3A is a cross-sectional schematic view for describing one processof a method of manufacturing the light receiving element illustrated inFIG. 1 .

FIG. 3B is a cross-sectional schematic view illustrating a processfollowing FIG. 3A.

FIG. 4A is a cross-sectional schematic view illustrating a processfollowing FIG. 3B.

FIG. 4B is a cross-sectional schematic view illustrating a processfollowing FIG. 4A.

FIG. 5A is a cross-sectional schematic view illustrating a processfollowing FIG. 4B.

FIG. 5B is a cross-sectional schematic view illustrating a processfollowing FIG. 5A.

FIG. 6A is a cross-sectional schematic view illustrating a processfollowing FIG. 5B.

FIG. 6B is a cross-sectional schematic view illustrating a processfollowing FIG. 6A.

FIG. 7A is a cross-sectional schematic view illustrating a processfollowing FIG. 6B.

FIG. 7B is a cross-sectional schematic view illustrating a processfollowing FIG. 7A.

FIG. 7C is a cross-sectional schematic view illustrating a processfollowing FIG. 7B.

FIG. 8A is a cross-sectional schematic view illustrating a processfollowing FIG. 7C.

FIG. 8B is a cross-sectional schematic view illustrating a processfollowing FIG. 8A.

FIG. 8C is a cross-sectional schematic view illustrating a processfollowing FIG. 8B.

FIG. 9 is a cross-sectional schematic view illustrating a schematicconfiguration of a light receiving element according to a modificationexample 1.

FIG. 10 is a cross-sectional schematic view illustrating a schematicconfiguration of a light receiving element according to a modificationexample 2.

FIG. 11 is a cross-sectional schematic view illustrating a schematicconfiguration of a light receiving element according to a secondembodiment of the present disclosure.

FIG. 12A is a plan schematic view illustrating an overall configurationof the light receiving element illustrated in FIG. 11 .

FIG. 12B is a cross-sectional schematic view illustrating the lightreceiving element taken along a line I-I illustrated in FIG. 12A.

FIG. 12C is a cross-sectional schematic view illustrating the lightreceiving element taken along a line II-II illustrated in FIG. 12A.

FIG. 13 is a cross-sectional schematic view illustrating a schematicconfiguration of a light receiving element according to a modificationexample 3.

FIG. 14 is a cross-sectional schematic view illustrating a schematicconfiguration of a light receiving element according to a modificationexample 4.

FIG. 15 is a cross-sectional schematic view illustrating a schematicconfiguration of a light receiving element according to a modificationexample 5.

FIG. 16 is a cross-sectional schematic view illustrating a schematicconfiguration of a light receiving element according to a modificationexample 6.

FIG. 17 is a block diagram illustrating a configuration of a solid-stateimaging device.

FIG. 18 is a schematic view illustrating a configuration example of astacked-type solid-state imaging device.

FIG. 19 is a functional block diagram illustrating an example of anelectronic apparatus (camera) including the solid-state imaging deviceillustrated in FIG. 17 .

FIG. 20 is a block diagram depicting an example of a schematicconfiguration of an in-vivo information acquisition system.

FIG. 21 is a view depicting an example of a schematic configuration ofan endoscopic surgery system to which the present technology may beapplied.

FIG. 22 is a block diagram depicting an example of a functionalconfiguration of a camera head and a camera control unit (CCU)illustrated in FIG. 21 .

FIG. 23 is a block diagram depicting an example of schematicconfiguration of a vehicle control system.

FIG. 24 is a diagram of assistance in explaining an example ofinstallation positions of an outside-vehicle information detectingsection and an imaging section.

MODES FOR CARRYING OUT THE INVENTION

Some embodiments of the present disclosure are described below in detailwith reference to the drawings. The following description is a specificexample of the present disclosure, and the present disclosure is notlimited to the following aspects. In addition, the present disclosure isnot limited to the arrangement, dimensions, dimensional ratios, and thelike of the constituent elements illustrated in the drawings. It is tobe noted that the description is given in the following order.

1. First Embodiment (An example of a light receiving element includingan electrode having a light-shielding property between pixels)

1-1. Configuration of Light Receiving Element

1-2. Method of Manufacturing Light Receiving Element

1-3. Operation of Light Receiving Element

1-4. Workings and Effects

2. Modification Examples

2-1. Modification Example 1 (An example of including a color filter andon-chip lens)

2-2. Modification Example 2 (An example of directly providing anelectrode having a light-shielding property over a photoelectricconverter)

3. Second Embodiment (An example of a light receiving element in whichan insulating layer is formed over a photoelectric converter)

3-1. Configuration of Light Receiving Element

3-2. Workings and Effects

4. Modification Examples

4-1. Modification Example 3 (An example of a light receiving element inwhich a light-shielding film is formed over a first electrode)

4-2. Modification Example 4 (An example of a light receiving element inwhich a light-shielding film is formed between an insulating layer and afirst electrode)

4-3. Modification Example 5 (An example of a light receiving element inwhich a carrier-induction layer is formed over a photoelectricconverter)

4-4. Modification Example 6 (An example of a light receiving elementwhich discharges electric charges from side opposite to a light incidentsurface)

5. Application Examples

First Embodiment

FIG. 1 schematically illustrates a cross-sectional configuration of alight receiving element (light receiving element 1) according to a firstembodiment of the present disclosure. The light receiving element 1 isapplied to, for example, an infrared sensor or the like using a compoundsemiconductor material such as a III-V group semiconductor or the like,and has a photoelectric conversion function to light having a wavelengthof a visible region (e.g., more than or equal to 380 nm and less than780 nm) to a short infrared region (e.g., more than or equal to 780 nmand less than 2400 nm), for example. The light receiving element 1 isprovided with a plurality of light receiving unit regions (pixels P)that are two-dimensionally disposed, for example. FIG. 1 illustrates across-sectional configuration of a portion corresponding to three pixelsP.

1-1. Configuration of Light Receiving Element

The light receiving element 1 has a stacked structure of an elementsubstrate 10 and a circuit board 20. One surface of the elementsubstrate 10 is a light incident surface (light incident surface S1),and a surface (another surface) opposite to the light incident surfaceSi is a surface (bonding surface S2) bonded to the circuit board 20. Theelement substrate 10 has a configuration in which interlayer insulatingfilms 18 (18B and 18A), a second contact layer 12, a photoelectricconversion layer 13, a first contact layer 14, and a first electrode 15are stacked in this order from the circuit board 20 side. In the presentembodiment, the second contact layer 12, the photoelectric conversionlayer 13, and the first contact layer 14 configures a photoelectricconverter 10S common to the plurality of pixels P, and the firstelectrode 15 having a light-shielding property is provided betweenpixels P adjacent to each other on the light incident surface S1 side ofthe photoelectric converter 10S.

As described above, the element substrate 10 includes the interlayerinsulating films 18B and 18A, the second contact layer 12, thephotoelectric conversion layer 13, the first contact layer 14, and thefirst electrode 15 in this order from a position close to the circuitboard 20. The interlayer insulating films 18 are provided with a wiringlayer 10W including a second electrode 11. A surface of thephotoelectric converter 10S that opposes the wiring layer 10W and an endsurface (side surface) of the photoelectric converter 10S are coveredwith an insulating film 16. The circuit board 20 includes a wiring layer20W in contact with the bonding surface S2 of the element substrate 10and a support base 21 that opposes the element substrate 10 with thewiring layer 20W interposed therebetween.

A pixel region R1, which is a light receiving region, is provided in acenter portion of the element substrate 10, and the photoelectricconverter 10S is disposed in the pixel region R1. In other words, aregion in which the photoelectric converter 10S is provided is the pixelregion R1. A peripheral region R2 surrounding the pixel region R1 isprovided outside the pixel region R1. The peripheral region R2 of theelement substrate 10 is provided with an embedded layer 17 along withthe insulating film 16. In the present embodiment, the first electrode15 is provided between pixels P adjacent to each other as describedabove, and is formed, for example, in a so-called lattice shape in planview. Therefore, in the light receiving element 1 of the presentembodiment, light enters the photoelectric converter 10S through thefirst contact layer 14 from the first electrode 15 provided between thepixels P. A signal charge photoelectrically converted by thephotoelectric converter 10S travels through the wiring layer 10W and isread out by the circuit board 20. Hereinafter, a configuration of eachsection will be described.

The wiring layer 10W includes, for example, the second electrode 11 andcontact electrodes 18EA and 18EB in the interlayer insulating films 18(18A and 18B).

The interlayer insulating films 18 (18A and 18B) are provided over thepixel region R1 and the peripheral region R2, and include the bondingsurface S2 with the circuit board 20. The bonding surface S2 in thepixel region R1 and the bonding surface in the peripheral region R2 formthe same plane. The interlayer insulating films 18A and 18B are in astacked structure, for example, the interlayer insulating film 18A isdisposed on side of the second contact layer 12, and the interlayerinsulating film 18B is disposed on the circuit board 20 side. Theinterlayer insulating films 18A and 18B include an inorganic insulatingmaterial, for example. Examples of the inorganic insulating materialinclude silicon nitride (SiN), aluminum oxide (Al₂O₃), silicon oxide(SiO₂), hafnium oxide (HfO₂), and the like. The interlayer insulatingfilms 18A and 18B may each be formed using inorganic insulatingmaterials that differ from each other, or may each be formed using thesame inorganic insulating material.

The second electrode 11 is an electrode (anode) to which a voltage forreading out a signal charge (a hole or an electron, hereinafter, forconvenience, described on the assumption that the signal charge is ahole) generated in the photoelectric conversion layer 13 is supplied,and is provided for each pixel P in the pixel region R1. The secondelectrode 11 provided in the wiring layer 10W is in contact with thesecond contact layer 12 of the photoelectric converter 10S viaconnection holes of the interlayer insulating film 18A and theinsulating film 16. Second electrodes 11 adjacent to each other areelectrically separated by the interlayer insulating film 18B and theinsulating film 16.

The second electrode 11 includes, for example, any one of titanium (Ti),tungsten (W), titanium nitride (TiN), platinum (Pt), gold (Au),germanium (Ge), palladium (Pd), zinc (Zn), nickel (Ni), and aluminum(Al), or an alloy containing at least one of those. The second electrode11 may be a single film of such materials, or may be a stacked film inwhich two or more materials are combined. For example, the secondelectrode 11 is configured as a stacked film of titanium and tungsten.

The contact electrode 18EA electrically couples the second electrode 11to the circuit board 20, and is provided for each pixel P in the pixelregion R1. The contact electrodes 18EA adjacent to each other areelectrically separated by the interlayer insulating film 18B.

The contact electrode 18EB electrically couples the first electrode 15to a wiring line (a wiring line 22CB to be described later) of thecircuit board 20, and is disposed in the peripheral region R2. Thecontact electrode 18EB is formed, for example, by the same process asthe contact electrode 18EA. The contact electrodes 18EA and 18EB eachinclude, for example, a copper (Cu) pad, and are exposed to the bondingsurface S2.

The photoelectric converter 10S includes, for example, the secondcontact layer 12, the photoelectric conversion layer 13, and the firstcontact layer 14, from a position close to the wiring layer 10W. Thesecond contact layer 12, the photoelectric conversion layer 13, and thefirst contact layer 14 have, for example, substantially the same planarshapes.

The second contact layer 12 is, for example, provided in common to allpixels P, and is disposed between the insulating film 16 and thephotoelectric conversion layer 13. The second contact layer 12electrically separates the pixels P adjacent to each other, and thesecond contact layer 12 is provided with, for example, a plurality ofdiffusion regions 12A. It is possible to suppress a dark current by thesecond contact layer 12 including a compound semiconductor materialhaving a band gap larger than a band gap of the compound semiconductormaterial included in the photoelectric conversion layer 13. For example,it is possible for the second contact layer 12 to include n-type InP(indium phosphide).

The diffusion regions 12A provided in the second contact layer 12 arespaced apart from each other. The diffusion region 12A is disposed foreach pixel P, and the second electrode 11 is coupled to each diffusionregion 12A. The diffusion region 12A reads out a signal charge generatedin the photoelectric conversion layer 13 for each pixel P, and includes,for example, a p-type impurity. As the p-type impurity, there are givenZn (zinc) and the like. In this manner, a p-n junction interface isformed between the diffusion region 12A and the second contact layer 12other than the diffusion region 12A, and the pixels P adjacent to eachother are electrically isolated. The diffusion region 12A is provided,for example, in a thickness direction of the second contact layer 12,and is also provided in a portion of a thickness direction of thephotoelectric conversion layer 13.

The photoelectric conversion layer 13 between the second electrode 11and the first electrode 15, more specifically, between the secondcontact layer 12 and the first contact layer 14, is provided in commonto all pixels P, for example. The photoelectric conversion layer 13absorbs light of a predetermined wavelength to generate a signal charge,and includes, for example, a compound semiconductor material such as aIII-V group semiconductor of i-type. Examples of the compoundsemiconductor material included in the photoelectric conversion layer 13include InGaAs (indium gallium arsenide), InAsSb (indium arsenideantimony), InAs (indium arsenide), InSb (indium antimony), HgCdTe(mercury cadmium tellurium), and the like. The photoelectric conversionlayer 13 may include Ge (germanium). In the photoelectric conversionlayer 13, photoelectric conversions are performed on light having awavelength of from a visible region to a short infrared region, forexample.

The first contact layer 14 is provided in common to all pixels P, forexample. The first contact layer 14 is provided between and in contactwith the photoelectric conversion layer 13 and the first electrode 15.The first contact layer 14 is a region through which an electric chargedischarged from the first electrode 15 travels, and includes, forexample, a compound semiconductor containing an n-type impurity. Forexample, it is possible for the first contact layer 14 to include n-typeInP (indium phosphorus). The first contact layer 14 has the thicknessof, for example, more than or equal to 20 nm and less than or equal to1000 nm.

The first electrode 15 has a structure in which a cap layer 15A and alight-shielding film 15B are stacked in this order, and is provided, forexample, in a lattice shape between the pixels P adjacent to each otherand provided over the first contact layer 14 (the light incident surfaceside). The first electrode 15 (cathode) is used to discharge electriccharges that are not used as signal charges among the electric chargesgenerated in the photoelectric conversion layer 13. For example, in acase where a hole is read out from the second electrode 11 as a signalcharge, the electron is discharged through the first electrode 15. Asdescribed above, by providing first electrode 15 in the lattice shape,the resistance of the extraction of electrons is reduced, the demand forreducing the resistance to the first contact layer 14 is reduced, andthis makes it possible to reduce the thickness of the first contactlayer 14.

The cap layer 15A includes a semiconductor material that is able toepitaxially grow on the first contact layer 14 of the photoelectricconverter 10S, and may include, for example, InGaAs, InAsSb, or thelike.

The light-shielding film 15B extends from the pixel region R1 to theperipheral region R2, and is provided over the cap layer 15A in thepixel region R1. That is, the light-shielding film 15B is provided, forexample, in a lattice shape between the pixels P adjacent to each otherin the pixel region R1. The light-shielding film 15B includes a metalfilm having a light-shielding property. Specifically, it is possible touse a tungsten (W) film, a copper (Cu) film, an aluminum (Al) film, asilver (Ag) film, or the like. The metal film is stacked over the caplayer 15A via a barrier metal film such as a titanium (Ti) film, atitanium nitride (TiN) film, or the like. That is, the light-shieldingfilm 15B has a stacked structure in which the barrier metal film and themetal film are stacked in order from the cap layer 15A side. As aresult, an ohmic contact is formed between the cap layer 15A and thelight-shielding film 15B. The thickness of the light-shielding film 15Bis, for example, preferably more than or equal to 50 nm and less than orequal to 1000 nm, and of these, the thickness of the barrier metal filmis, for example, more than or equal to 10 nm and less than or equal to500 nm, and the thickness of the metal film is, for example, more thanor equal to 50 nm and less than or equal to 1000 nm.

In FIG. 1 , the cross-sectional shape of the first electrode 15 is arectangular shape in which the cap layer 15A and the light-shieldingfilm 15B has a continuous common side, but is not limited thereto. Forexample, as illustrated in FIG. 2 (A), slopes may be formed on sidesurfaces of the light-shielding film 15B, or as illustrated in FIG. 2(B), side surfaces of the light-shielding film 15B may have slopes andthe cap layer 15A may be etched inward of the bottom surface of thelight-shielding film 15B. Further, as illustrated in FIG. 2 (C), the caplayer 15A and the metal film portion may have the same side surface, andonly the barrier metal film between the cap layer 15A and the metal filmmay be etched inward.

The first electrode 15 is formed, although the detail thereof isdescribed later, for example, by patterning the light-shielding film 15Bby dry etching and then patterning the cap layer 15A by wet etchingusing the light-shielding film 15B as a metal mask. In a case where thecap layer 15A is patterned by wet etching as described above, thecross-sectional shape of the cap layer 15A (for example, N+InGaAs layer)patterned in a lattice shape has different characteristics depending oncrystallographic plane orientations. Generally, an InGaAs/InP crystal ina 100 plane is processed to have an inverse taper in a (011) planecross-sectional direction and a forward taper in the direction rotatedby 90 degrees with respect to a (011) plane.

Although not illustrated, a passivation film is provided over thesurface of the light receiving element 1. The passivation film may havean anti-reflection function. Examples of the passivation film mayinclude silicon nitride (SiN), aluminum oxide (Al₂O₃), silicon oxide(SiO₂), tantalum oxide (Ta₂O₃), and the like.

The insulating film 16 is provided between the second contact layer 12and the wiring layer 10W, covers a bottom surface and an end surface ofthe second contact layer 12, an end surface of the photoelectricconversion layer 13, an end surface of the first contact layer 14, andan end surface of the cap layer 15A, and is in contact with thelight-shielding film 15B in the peripheral region R2. The insulatingfilm 16 includes, for example, an oxide such as silicon oxide (SiO_(X)),aluminum oxide (Al₂O₃), or the like. The insulating film 16 may beconfigured as a stacked structure including a plurality of films. Theinsulating film 16 may include a silicon (Si)-based insulating materialsuch as silicon oxynitride (SiON), carbon-containing silicon oxide(SiOC), silicon nitride (SiN), silicon carbide (SiC), or the like, forexample.

The embedded layer 17 fills a step between a temporary substrate (atemporary substrate 73 in FIG. 3B to be described later) and thephotoelectric converter 10S in a manufacturing process of the lightreceiving element 1. As will be described later in detail, in thepresent embodiment, since the embedded layer 17 is formed, it ispossible to suppress generation of a defect in the manufacturing processcaused by the step between the photoelectric converter 10S and thetemporary substrate 73.

The embedded layer 17 is provided between the wiring layer 10W and thelight-shielding film 15B, and has a thickness more than or equal to thethickness of the photoelectric converter 10S, for example. Here, sincethe embedded layer 17 is provided so as to surround the photoelectricconverter 10S, a region (peripheral region R2) is formed around thephotoelectric converter 10S. Thus, it is possible to provide the bondingsurface S2 with the circuit board 20 in the peripheral region R2. If thebonding surface S2 is formed in the peripheral region R2, the thicknessof the embedded layer 17 may be reduced; however, it is preferable thatthe embedded layer 17 cover the photoelectric converter 10S over thethickness direction, and that the embedded layer 17 cover the entiresurface of the end surface of the photoelectric converter 10S. Bycovering the entire end surface of the photoelectric converter 10S withthe embedded layer 17 via the insulating film 16, it is possible toeffectively suppress ingress of water into the photoelectric converter10S.

A surface of the embedded layer 17 on the bonding surface S2 side isflattened, and is provided with the wiring layer 10W on the flattenedsurface of the embedded layer 17 in the peripheral region R2. For theembedded layer 17, for example, it is possible to use an inorganicinsulating material such as silicon oxide (SiO_(X)), silicon nitride(SiN), silicon oxynitride (SiON), carbon-containing silicon oxide(SiOC), silicon carbide (SiC), or the like.

The embedded layer 17 is provided with a penetration electrode 17V. Thepenetration electrode 17V couples the first electrode 15 and the wiringlayer 20W provided in the circuit board 20. One side of the penetrationelectrode 17V is coupled to the first electrode 15, and another side ofthe penetration electrode 17V passes through the interlayer insulatingfilm 18A and is coupled to the contact electrode 18EB. The contactelectrode 18EB is provided in the peripheral region R2 in the interlayerinsulating film 18B, and is electrically coupled to the wiring line 22CBprovided in the peripheral region R2 in the wiring layer 20W.

The support base 21 supports the wiring layer 20W and includes, forexample, silicon (Si). The wiring layer 20W includes, for example,contact electrodes 22EA and 22EB, a pixel circuit 22CA, the wiring line22CB, and a pad electrode 22P, in interlayer insulating films 22 (22Aand 22B). The interlayer insulating films 22A and 22B each include aninorganic insulating material, for example. Examples of the inorganicinsulating material include silicon nitride (SiN), aluminum oxide(Al₂O₃), silicon oxide (SiO₂), hafnium oxide (HfO₂), and the like. Theinterlayer insulating films 22A and the 22B may be formed usingdifferent inorganic insulating materials from each other, or may beformed using the same inorganic insulating material.

The contact electrode 22EA is provided, for example, in the pixel regionR1, electrically couples the second electrode 11 and the pixel circuit22CA, and is in contact with the contact electrode 18EA at the bondingsurface S2 of the element substrate 10. Contact electrodes 22EA adjacentto each other are electrically separated by the interlayer insulatingfilms 22A and 22B.

The contact electrode 22EB is provided, for example, in the peripheralregion R2, electrically couples the first electrode 15 and the wiringline 22CB of the circuit board 20, and is in contact with the contactelectrode 18EB at the bonding surface S2 of the element substrate 10.The contact electrode 22EB is formed by the same process as the contactelectrode 22EA, for example. The penetration electrode 17V may becoupled to the wiring line 22CB without providing the contact electrodes18EB and 22EB.

The contact electrodes 22EA and 22EB each include, for example, a copper(Cu) pad, and are exposed on a surface, of the circuit board 20,opposing the element substrate 10. That is, a Cu—Cu bonding is formedeach of between the contact electrode 18EA and the contact electrode22EA and between the contact electrode 18EB and the contact electrode22EB.

The pixel circuit 22CA is provided for each pixel P in the pixel regionR1, for example, and is coupled to the contact electrode 22EA. The pixelcircuit 22CA includes a ROIC. The wiring line 22CB is provided in, forexample, the peripheral region R2, is coupled to the contact electrode22EB, and is coupled to, for example, a predetermined electricpotential. Accordingly, one type of the charges (e.g., holes) generatedin the photoelectric conversion layer 13 is read out from the secondelectrode 11 to the pixel circuit 22CA via the contact electrodes 18EAand 22EA, and the other type of the charges (e.g., electrons) generatedin the photoelectric conversion layer 13 is discharged from the firstelectrode 15 to the predetermined electric potential via the penetrationelectrode 17V and the contact electrodes 18EB and 22EB.

The pad electrode 22P electrically couples to the outside. The lightreceiving element 1 is provided with an opening H which penetrates theelement substrate 10 and reaches the pad electrode 22P, and iselectrically coupled to the outside via the opening H. The coupling isachieved by, for example, wire bonding or bumping.

1-2. Method of Manufacturing Light Receiving Element

It is possible to manufacture the light receiving element 1 as follows,for example. FIGS. 3A to 8C illustrate processes of manufacturing thelight receiving element 1 in process order.

First, as illustrated in FIG. 3A, on a growth substrate 71, for example,a buffer layer 74B including n-type InP, a stopper layer 74S includingi-type InGaAs, the photoelectric converter 10S, and the cap layer 15Aincluding i-type InGaAs are formed in this order by epitaxial growth.The diameter of the growth substrate 71 is, for example, less than orequal to 6 inches. As the photoelectric converter 10S, for example, thesecond contact layer 12 including n-type InP, the photoelectricconversion layer 13 including i-type or n-type InGaAs, and the firstcontact layer 14 including n-type InP are formed in this order.

Subsequently, as illustrated in FIG. 3B, the growth substrate 71 isbonded to the temporary substrate 73 having a large diameter with anadhesion layer B therebetween. At this time, the cap layer 15A isinterposed between the adhesion layer B and the first contact layer 14.For example, a silicon (Si) substrate having a larger diameter than thegrowth substrate 71 is used for the temporary substrate 73. The diameterof the temporary substrate 73 is, for example, 8 inches to 12 inches. Bybonding the growth substrate 71 having a small diameter to the temporarysubstrate 73 having a large diameter, it becomes possible to use variousdevices to be used for substrates having large diameters when formingelement substrate 10. As a result, for example, it is possible to formthe bonding between the circuit board 20 and the element substrate 10into a Cu—Cu bonding, and to miniaturize the pixel P. The bonding of thegrowth substrate 71 to the temporary substrate 73 may be performed byplasma-activated bonding, room-temperature bonding, bonding using anadhesive (adhesive bonding), or the like. Thus, for example, thephotoelectric converter 10S of a wafer shape is bonded to the temporarysubstrate 73. The photoelectric converter 10S is not limited to thewafer shape, and may be fragmented into chips.

After the growth substrate 71 on which the photoelectric converter 10Sis formed is bonded to the temporary substrate 73, the growth substrate71 is removed as illustrated in the drawing 4A. It is possible to removethe growth substrate 71 by mechanical grinding, CMP (Chemical MechanicalPolishing), wet etching, dry etching, or the like.

Subsequently, as illustrated in FIG. 4B, positional deviation of thephotoelectric converter 10S with respect to the temporary substrate 73is corrected. Specifically, for example, photolithography and etchingare used to correct the positional deviation of the photoelectricconverter 10S. A resist (resist PR) is formed over the photoelectricconverter 10S, and the photoelectric converter 10S is etched asappropriate. As the etching, dry etching, wet etching, or the like maybe used. This removes unwanted portions of the photoelectric converter10S and leaves the photoelectric converter 10S only in a defined region(pixel region R1) of the temporary substrate 73. As described above, thepositional deviation of the photoelectric converter 10S with respect tothe temporary substrate 73 is corrected, and thus, it is possible tosuppress the generation of the misalignment in the later process, and toeasily form the light receiving element 1 having a desiredconfiguration.

After the positional deviation of the photoelectric converter 10S withrespect to temporary substrate 73 is corrected, as illustrated in FIG.5A, the insulating film 16 film is formed over the entire surface of thetemporary substrate 73. Subsequently, the diffusion region 12A is formedfor each pixel P in the photoelectric converter 10S. As a result,element isolation is performed. For forming the diffusion region 12A,for example, the insulating film 16 is used as a hard mask.Specifically, after a mask of a predetermined shape is formed on thesecond contact layer 12, an opening 16H is formed on the insulating film16 by etching. Thereafter, the resist is stripped, and vapor-phasediffusion of a p-type impurity is performed using the insulating film 16as a hard mask. As a result, the diffusion region 12A is formed in theselective region. The diffusion region 12A may be formed by ionimplantation or the like using a resist mask. Here, the diffusion region12A is formed in the photoelectric converter 10S provided over thetemporary substrate 73 having a large diameter; therefore, it ispossible to miniaturize the pixel P.

After forming the diffusion region 12A over the photoelectric converter10S, as illustrated in FIG. 5B, an insulating material film is formedover the entire surface of the temporary substrate 73, and then isflattened by, for example, CMP. Thus, the embedded layer 17 is formed inthe peripheral region R2 of the photoelectric converter 10S, theembedded layer 17 having the same plane as the top surface (the planefurthest from the temporary substrate 73) of the photoelectric converter10S. It is to be noted that the diffusion region 12A and the embeddedlayer 17 may be formed in the reverse order, or the diffusion region 12Aand the embedded layer 17 may be formed in this order after thepositional deviation of the photoelectric converter 10S with respect tothe temporary substrate 73 is corrected.

Subsequently, the wiring layer 10W including the second electrode 11 isformed over the photoelectric converter 10S. First, an insulatingmaterial film is formed over the entire surface of the photoelectricconverter 10S and the embedded layer 17, and then an opening is formed.The opening is subjected to a CVD (Chemical Vapor Deposition) method, aPVD (Physical Vapor Deposition) method, an ALD (Atomic Layer Deposition)method, an evaporation method, or the like, to thereby form, forexample, a stacked film of titanium (Ti)/tungsten (W), and thereafter,the stacked film is patterned by photolithography and etching. Thus, thesecond electrode 11 is formed. Thereafter, an insulating material filmis further formed so as to cover the second electrode 11, and thenflattened by, for example, CMP, to form the interlayer insulating film18A.

Next, an insulating material film is formed over the interlayerinsulating film 18A, and is flattened by, for example, CMP; thus, theinterlayer insulating film 18B is formed. Thereafter, as illustrated inFIG. 6A, an opening 18H1 and an opening 18H2 are formed over thephotoelectric converter 10S (pixel region R1) and the region (peripheralregion R2) other than photoelectric converter 10S, respectively. It isto be noted that, in the opening 18H1 formed over the photoelectricconverter 10S, a portion of the second electrode 11 is exposed to thebottom surface of the opening 18H1. A copper (Cu) film is formed on eachof the openings 18H1 and 18H2 of the interlayer insulating film 18B byvapor deposition, PVD, plating, or the like, and then the surface of thecopper film is polished by, for example, CMP, to thereby form thecontact electrodes 18EA and 18EB. As a result, the wiring layer 10Wincluding the second electrode 11, and the contact electrodes 18EA and18EB is formed. Here, the wiring layer 10W is formed on the temporarysubstrate 73 having a large diameter; therefore, it becomes possible touse various devices to be used for substrates having large diameters. Inaddition, since the cap layer 15A is interposed between the adhesionlayer B and the first contact layer 14 in the processes of removing thegrowth substrate 71, forming the diffusion region 12A, forming thewiring layer 10W, and the like, it is possible to suppress the decreasein characteristics of the photoelectric converter 10S, the peeling offof films, and the like.

After the wiring layer 10W is formed, as illustrated in FIG. 6B, thecircuit board 20 is bonded to the temporary substrate 73 with the wiringlayer 10W interposed therebetween. At this time, the wiring layer 20W isformed in advance on the circuit board 20. The wiring layer 20W of thecircuit board 20 includes the contact electrodes 22EA and 22EB eachhaving a pad structure, and when the circuit board 20 is bonded to thetemporary substrate 73, for example, the contact electrodes 22EA and22EB of the wiring layer 20W and the contact electrodes 18EA and 18EB ofthe wiring layer 10W are bonded, respectively, by Cu—Cu bonding. Morespecifically, in the pixel region R1, the bonding surface S2 in whichthe contact electrode 18EA and the contact electrode 22EA are bonded isformed, and in the peripheral region R2, the bonding surface S2 in whichthe contact electrode 18EB and the contact electrode 22EB are bonded isformed. Here, the peripheral region R2 of the element substrate 10 isalso bonded to the circuit board 20.

Hereinafter, description will be made with reference to the drawingscorresponding to the cross-sectional configuration of the lightreceiving element 1 illustrated in FIG. 1 will be described. Afterattaching the circuit board 20 to the temporary substrate 73, thetemporary substrate 73 is removed as illustrated in FIG. 7A. It ispossible to remove the temporary substrate 73 by, for example,mechanical grinding, wet etching, dry etching, or the like.

Subsequently, as illustrated in FIG. 7B, the adhesion layer B in thepixel region R1 is removed by, for example, wet etching, to therebyprovide an opening BH. For the wet etching performed on the adhesionlayer B, for example, it is possible to use HF (Hydrogen Fluoride), BHF(Buffered Hydrogen Fluoride), or the like. Next, as illustrated in FIG.7C, the light-shielding film 15B is formed over the entire surface ofthe embedded layer 17, the adhesion layer B, and the cap layer 15A by asputtering method or a CVD method.

Subsequently, as illustrated in FIG. 8A, masks of predetermined shapesare formed on the light-shielding film 15B. Next, as illustrated in FIG.8B, the light-shielding film 15B is patterned into a lattice shape bydry etching. At this time, ion damage and optical damage due to the dryetching are absorbed by the cap layer 15A, and damage to the firstcontact layer 14 is reduced. Subsequently, as illustrated in FIG. 8C,the cap layer 15A is patterned by wet etching using the light-shieldingfilm 15B patterned in the lattice shape as a mask.

Finally, over the first contact layer 14, the first electrode 15, andthe embedded layer 17, which are exposed by removing the cap layer 15A,the passivation film (not illustrated) is formed, and thereafter, thepenetration electrode 17V is formed through the embedded layer 17 toelectrically couples the first electrode 15 and the circuit board 20.Subsequently, the opening H is formed which penetrates the elementsubstrate 10 and reaches the pad electrode 22P of the circuit board 20.Thus, the light receiving element 1 illustrated in FIG. 1 is completed.

1-3. Operation of Light Receiving Element

In the light receiving element 1, when light (e.g. light having awavelength of the visible region and the infrared region) enters thephotoelectric conversion layer 13 via a passivation film 19, the firstelectrode 15, and the first contact layer 14, the light is absorbed inthe photoelectric conversion layer 13. As a result, pairs of holes andelectrons are generated (photoelectrically converted) in thephotoelectric conversion layer 13. At this time, for example, when apredetermined voltage is applied to the second electrode 11, an electricpotential gradient is generated in the photoelectric conversion layer13, and one type of the generated charges (e.g., holes) travels to thediffusion region 12A as a signal charge, and is collected from thediffusion region 12A to the second electrode 11. The signal chargetravels to the pixel circuit 22CA via the contact electrodes 18EA and22EA, and is read out for each pixel P.

1-4. Workings and Effects

As described above, in an image sensor including s semiconductor element(light receiving element) in which a photoelectric conversion layer isformed using a compound semiconductor, leakage of light from an adjacentpixel region occurs and color mixture occurs in a case where alight-shielding film is not disposed between pixels, similarly to a caseof a light receiving element in which Si is used.

Incidentally, in an infrared sensor, an improvement in sensitivity isdemanded. A light receiving element included in the infrared sensor isgenerally provided with a transparent electrode on light incidentsurface side, and the transparent electrode is responsible for readingout electric charges (holes or electrons) generated by photoelectricconversion. In addition, as described above, in the light receivingelement in which the compound semiconductor is used for thephotoelectric conversion layer, the transparent electrode may notnecessarily be included, but in this case, it is necessary to increasethe thickness of the compound semiconductor layer (e.g., n+InP layer) inorder to reduce the wiring resistance for reading out electric charges.However, the n+InP layer has a high visible-light absorbance, and thereis an issue that the n+InP layer lowers sensitivity of the visibleregion.

In contrast, in the present embodiment, the first electrode 15 having alight-shielding property is provided between the pixels P adjacent toeach other and provided on the light incident surface S1 side. In thismanner, by forming the first electrode 15 between the pixels P adjacentto each other, leakage of light from the adjacent pixel region isreduced. The first electrode 15 has a stacked structure of the cap layer15A and the light-shielding film 15B formed using, for example, a metalfilm. In this manner, with the structure in which the cap layer 15A andthe light-shielding film 15B are stacked in this order, it is possibleto prevent damage to the photoelectric converter 10S (specifically, thefirst contact layer 14) at the time of patterning the metal filmincluded in the light-shielding film 15B. Further, by using the caplayer 15A as the first electrode 15, it is possible to reduce thecontact resistance between the photoelectric converter 10S(specifically, the first contact layer 14) and the first electrode 15.Still further, by forming the first electrode 15 in, for example, alattice shape, the wiring resistance of the first electrode 15 thatdischarges electrons is reduced, for example. As a result, it becomesunnecessary to form a transparent electrode on the light incidentsurface S1 side, it becomes unnecessary to increase the thickness of thefirst contact layer 14 included in the photoelectric converter 10S, andit is possible to reduce the absorbance of the visible light by thefirst contact layer 14.

As described above, in the light receiving element 1 of the presentembodiment, the first electrode 15 in which the cap layer 15A and thelight-shielding film 15B are stacked in a lattice shape, for example, isprovided between the pixels P adjacent to each other and provided on thelight incident surface S1 side; therefore, it is not necessary to form atransparent electrode or to increase the thickness of the first contactlayer 14. In addition, it is possible to reduce damage to thephotoelectric converter (specifically, the first contact layer 14) atthe time of patterning the light-shielding film 15B. Therefore, it ispossible to improve the sensitivity.

Further, in the present embodiment, the light-shielding film 15B has astacked structure in which the barrier metal and the metal film arestacked in this order on the cap layer 15A. As a result, the ohmiccontact is formed between the cap layer 15A and the light-shielding film15B. Therefore, it is possible to further reduce the contact resistancebetween the photoelectric converter 10S (specifically, the first contactlayer 14) and the first electrode 15, and to further improve thesensitivity.

Moreover, in the present embodiment, the cap layer 15A is patterned bywet etching; therefore, it is possible to reduce damage to the firstcontact layer 14. Accordingly, it is possible to reduce the generationof the dark current.

Next, a second embodiment and modification examples 1 to 6 will bedescribed. Hereinafter, the similar components to those of theembodiment described above are denoted by the same reference numerals,and description thereof is omitted as appropriate.

2. Modification Examples 2-1. Modification Example 1

FIG. 9 schematically illustrates a cross-sectional configuration of alight receiving element (light receiving element 1A) according to apresent modification example (modification example 1) of the presentdisclosure. The light receiving element 1A is applied to, for example,similarly to the light receiving element 1 in the above embodiment, aninfrared sensor or the like using a compound semiconductor material suchas a III-V group semiconductor or the like, and has a photoelectricconversion function to light having a wavelength of a visible region(e.g., more than or equal to 380 nm and less than 780 nm) to a shortinfrared region (e.g., more than or equal to 780 nm and less than 2400nm), for example. The light receiving element 1 is provided with aplurality of light receiving unit regions (pixels P) that aretwo-dimensionally disposed, for example. The light receiving element 1Aof the present modification example differs from the above embodiment inthat a color filter (CF) layer 31 having color filters of, for example,red (31R), green (31G), and blue (31B), and an on-chip lens 32 areprovided in this order on each pixel P disposed in the pixel region R1on the light incident surface side.

It is to be noted that the present modification example is applicablenot only to the light receiving element 1 according to the above firstembodiment but also to a light receiving element 2, light receivingelements 3A to 3E described later in the same manner.

2-2. Modification Example 2

FIG. 10 schematically illustrates a cross-sectional configuration of alight receiving element (light receiving element 2) according to amodification example (modification example 2) of the present disclosure.The light receiving element 2 is applied to, for example, similarly tothe light receiving element 1 in the above embodiment, an infraredsensor or the like using a compound semiconductor material such as aIII-V group semiconductor or the like, and has a photoelectricconversion function to light having a wavelength of a visible region(e.g., more than or equal to 380 nm and less than 780 nm) to a shortinfrared region (e.g., more than or equal to 780 nm and less than 2400nm), for example. The light receiving element 2 is provided with aplurality of two-dimensionally disposed light receiving unit regions(pixels P), for example. FIG. 10 illustrates a cross-sectionalconfiguration of a portion corresponding to three pixels P.

The light receiving element 2 has a stacked structure of the elementsubstrate 10 and the circuit board 20, similarly to the aboveembodiment. One surface of the element substrate 10 is the lightincident surface (light incident surface Si), and a surface opposite tothe light incident surface S1 is a surface (bonding surface S2) bondedto the circuit board 20. The element substrate 10 has the interlayerinsulating films 18 (18B and 18A), the second contact layer 12, thephotoelectric conversion layer 13, the first contact layer 14, and thefirst electrode 15 stacked in this order, and has a photoelectricconverter 10S common to the plurality of pixels P. In the presentembodiment, first electrodes 35 (35A and 35B) having a light-shieldingproperty are provided between the plurality of pixels P on the lightincident surface S1 side of the photoelectric converter 10S.

The first electrode 35A is provided over the first contact layer 14, forexample, between the plurality of pixels P adjacent to each other in aso-called lattice shape, and is provided so as to penetrate thepassivation film 19. The first electrode 35A is preferably formed usinga metal which has conductivity and is able to form an ohmic junction tothe first contact layer 14. The first electrode 35A may have either asingle-layer structure or a stacked structure, and preferably has astructure in which, for example, a barrier metal film and a metal filmare stacked in this order from the first contact layer 14 side. As thebarrier metal film, it is possible to use a titanium (Ti) film, atitanium nitride (TiN) film, or the like. As the metal film, it ispossible to use a tungsten (W) film, a copper (Cu) film, an aluminum(Al) film, a silver (Ag) film, or the like. Accordingly, an ohmiccontact is formed between the first contact layer 14 and the firstelectrode 15.

As illustrated in FIG. 10 , for example, the first electrode 35B iselectrically coupled to the wiring line 22CB via the penetrationelectrode 17V and the contact electrodes 18EB and 22EB in the peripheralregion R2. The wiring line 22CB is coupled to a predetermined electricpotential, for example, as described above. It is possible to setoptionally the electric potential of the wiring line 2CB. For example,as described above, in a case where the electrons are taken out from thefirst electrode 35B, it is possible to promote the discharge ofelectrons by setting a positive voltage. Alternatively, the firstelectrode 35B may be directly coupled to an electrode outside the chipwithout using the penetration electrode 17V or the like.

As described above, in the light receiving element 2 according to thepresent modification example, the first electrode 35 is formed in thelattice shape between the pixels P adjacent to each other in a planview, for example; therefore, the wiring resistance of the firstelectrode 35 is reduced. Therefore, it is possible to reduce thethickness of the first contact layer 14 and to improve the sensitivity.

Further, in the present modification example, the first electrodes 35each having a light-shielding property are directly provided over thefirst contact layer 14; therefore, it is possible to shorten themanufacturing process and to further reduce the leakage of light fromthe adjacent pixel region as compared to the above embodiment. That is,the light-shielding performance owing to the first electrodes 35 isfurther improved, and it is possible to further reduce the generation ofcolor mixture.

3. Second Embodiment

FIG. 11 schematically illustrates a cross-sectional configuration of alight receiving element (light receiving element 3A) according to asecond embodiment of the present disclosure. FIG. 12 each schematicallyillustrate an overall plan configuration of the light receiving element3A illustrated in FIG. 1 . The light receiving element 3A is applied to,for example, an infrared sensor or the like using a compoundsemiconductor material such as a III-V group semiconductor or the like,and has a photoelectric conversion function to light having a wavelengthof a visible region (e.g., more than or equal to 380 nm and less than780 nm) to a short infrared region (e.g., more than or equal to 780 nmand less than 2400 nm), for example. The light receiving element 3A isprovided with a plurality of light receiving unit regions (pixels P)that are two-dimensionally disposed, for example. FIG. 11 illustrates across-sectional configuration of a portion corresponding to three pixelsP.

3-1. Configuration of Light Receiving Element

The light receiving element 3A has a stacked structure of an elementsubstrate 40 and a circuit board 50. One surface of the elementsubstrate 40 is a light incident surface (light incident surface S1),and a surface (another surface) opposite to the light incident surfaceS1 is a surface (bonding surface S2) bonded to the circuit board 50. Theelement substrate 40 has a structure in which interlayer insulatingfilms 48 (48B and 48A), a second contact layer 42, a photoelectricconversion layer 43, a first contact layer 44, and a first electrode 45are stacked in this order from the circuit board 50 side, and the secondcontact layer 42, the photoelectric conversion layer 43, and the firstcontact layer 44 configures a photoelectric converter 40S common to theplurality of pixels P. In the present embodiment, for example, the firstelectrode 45 common to each pixel is provided via the insulating layer49 on the light incident surface S1 side of the photoelectric converter40S.

The element substrate 40 includes a wiring layer 40W including theinterlayer insulating films 48B and 48A and the second electrode 41, thephotoelectric converter 40S, and the first electrode 45 in this orderfrom a position close to the circuit board 50. A surface of thephotoelectric converter 40S that opposes the wiring layer 40W and an endsurface (side surface) of the photoelectric converter 40S are coveredwith an insulating film 46. The circuit board 50 includes a wiring layer50W in contact with the bonding surface S2 of the element substrate 40and a support base 51 that opposes the element substrate 40 with thewiring layer 50W interposed therebetween.

A pixel region R1, which is a light receiving region, is provided in acenter portion of the element substrate 40, and the photoelectricconverter 40S is disposed in the pixel region R1. In other words, aregion in which the photoelectric converter 40S is provided is the pixelregion R1. A peripheral region R2 surrounding the pixel region R1 isprovided outside the pixel region R1. The peripheral region R2 of theelement substrate 40 is provided with an embedded layer 47 along withthe insulating film 46. In the present embodiment, as described above,the first electrode 45 is provided over the photoelectric converter 40Svia the insulating layer 49. A signal charge photoelectrically convertedby the photoelectric converter 40S travels through the wiring layer 40Wand is read out by the circuit board 50. Hereinafter, a configuration ofeach section will be described.

The wiring layer 40W includes, for example, the second electrode 41 andcontact electrodes 48EA and 48EB in the interlayer insulating films 48(48A and 48B).

The interlayer insulating films 48 (48A and 48B) are provided over thepixel region R1 and the peripheral region R2, and include the bondingsurface S2 with the circuit board 50. The bonding surface S2 in thepixel region R1 and the bonding surface in the peripheral region R2 formthe same plane. The interlayer insulating films 48A and 48B are in astacked structure, for example, the interlayer insulating film 48A isdisposed on the second contact layer 42 side, and the interlayerinsulating film 48B is disposed on the circuit board 50 side. Theinterlayer insulating films 48A and 48B include an inorganic insulatingmaterial, for example. Examples of the inorganic insulating materialinclude silicon nitride (SiN), aluminum oxide (Al₂O₃), silicon oxide(SiO₂), hafnium oxide (HfO₂), and the like. The interlayer insulatingfilms 48A and 48B may each be formed using inorganic insulatingmaterials that differ from each other, or may each be formed using thesame inorganic insulating material.

The second electrode 41 is an electrode (anode) to which a voltage forreading out a signal charge (a hole or an electron, hereinafter, forconvenience, described on the assumption that the signal charge is ahole) generated in the photoelectric conversion layer 43 is supplied,and is provided for each pixel P in the pixel region R1. The secondelectrode 41 provided in the wiring layer 40W is in contact with thephotoelectric converter 40S (more specifically, the second contact layer42 to be described later) via connection holes of the interlayerinsulating film 18A and the insulating film 46. Second electrodes 41adjacent to each other are electrically separated by the interlayerinsulating film 48B and the insulating film 46.

The second electrode 41 includes, for example, any one of titanium (Ti),tungsten (W), titanium nitride (TiN), platinum (Pt), gold (Au),germanium (Ge), palladium (Pd), zinc (Zn), nickel (Ni), and aluminum(Al), or an alloy containing at least one of those. The second electrode41 may be a single film of such materials, or may be a stacked film inwhich two or more materials are combined. For example, the secondelectrode 41 is configured as a stacked film of titanium and tungsten.

The contact electrode 48EA electrically couples the second electrode 41to the circuit board 50, and is provided for each pixel P in the pixelregion R1. The contact electrodes 48EA adjacent to each other areelectrically separated by the interlayer insulating film 48B.

The contact electrode 48EB electrically couples the first electrode 45to a wiring line (a wiring line 52CB to be described later) of thecircuit board 50, and is disposed in the peripheral region R2. Thecontact electrode 48EB is formed, for example, by the same process asthe contact electrode 48EA. The contact electrodes 48EA and 48EB eachinclude, for example, a copper (Cu) pad, and are exposed to the bondingsurface S2.

The photoelectric converter 40S includes, for example, the secondcontact layer 42, the photoelectric conversion layer 43, and the firstcontact layer 44, from a position close to the wiring layer 40W. Thesecond contact layer 42, the photoelectric conversion layer 43, and thefirst contact layer 44 have substantially the same planar shapes.

The second contact layer 42 is, for example, provided in common to allpixels P, and is disposed between the insulating film 46 and thephotoelectric conversion layer 43. The second contact layer 42electrically separates the pixels P adjacent to each other, and thesecond contact layer 42 is provided with, for example, a plurality ofdiffusion regions 12A. It is possible to suppress a dark current by thesecond contact layer 42 including a compound semiconductor materialhaving a band gap larger than a band gap of the compound semiconductormaterial included in the photoelectric conversion layer 43. For example,it is possible for the second contact layer 42 to include n-type InP(indium phosphide).

The diffusion regions 12A provided in the second contact layer 42 arespaced apart from each other. The diffusion region 12A is disposed foreach pixel P, and the second electrode 41 is coupled to each diffusionregion 12A. The diffusion region 12A reads out a signal charge generatedin the photoelectric conversion layer 43 for each pixel P, and includes,for example, a p-type impurity. As the p-type impurity, there are givenZn (zinc) and the like. In this manner, a p-n junction interface isformed between the diffusion region 12A and the second contact layer 42other than the diffusion region 12A, and the pixels P adjacent to eachother are electrically isolated. The diffusion region 12A is provided,for example, in a thickness direction of the second contact layer 42,and is also provided in a portion of a thickness direction of thephotoelectric conversion layer 43.

The photoelectric conversion layer 43 between the second electrode 41and the first electrode 45, more specifically, between the secondcontact layer 42 and the first contact layer 44, is provided in commonto all pixels P, for example. The photoelectric conversion layer 43absorbs light of a predetermined wavelength to generate a signal charge,and includes, for example, a compound semiconductor material such as aIII-V group semiconductor of i-type. Examples of the compoundsemiconductor material included in the photoelectric conversion layer 43include InGaAs (indium gallium arsenide), InAsSb (indium arsenideantimony), InAs (indium arsenide), InSb (indium antimony), HgCdTe(mercury cadmium tellurium), and the like. The photoelectric conversionlayer 43 may include Ge (germanium). In the photoelectric conversionlayer 43, photoelectric conversions are performed on light having awavelength of from a visible region to a short infrared region, forexample.

The first contact layer 44 is provided in common to all pixels P, forexample. The first contact layer 44 is provided between and in contactwith the photoelectric conversion layer 43 and the first electrode 45.The first contact layer 44 is a region through which an electric chargedischarged from the first electrode 45 travels, and includes, forexample, a compound semiconductor containing an n-type impurity. Forexample, it is possible for the first contact layer 44 to include n-typeInP (indium phosphorus). The first contact layer 44 has the thicknessof, for example, more than or equal to 10 nm and less than or equal to300 nm.

The insulating layer 49 controls a carrier density of the first contactlayer 44, and is configured as a single layer film of, for example,silicon oxide (SiO_(X)), silicon nitride (SiN), and silicon oxynitride(SiON), or a stacked film thereof. The thickness of the insulating layer49 is, for example, more than or equal to 10 nm and less than or equalto 200 nm.

The first electrode 45 includes first electrodes 45A and 45B separatedfrom each other. The first electrode 45A is provided over the entiresurface of the pixel region R1, for example, as an electrode common toall pixels P. The first electrode 45B is provided in the peripheralregion R2 and is electrically coupled to the first contact layer 44. Thefirst electrode 45 (in particular, the first electrode 45B) (cathode) isused to discharge electric charges that are not used as signal chargesamong the electric charges generated in the photoelectric conversionlayer 43. The first electrode 45 includes, for example, a conductivefilm that is able to transmit incident light such as infrared light. Asa material of the first electrode 45, for example, it is possible to usea transparent conductive material such as ITO (Indium Tin Oxide), ITiO(In₂O₃—TiO₂), or the like. It is to be noted that the first electrode45B may include a metal film included in a light-shielding film 61 inaddition to the transparent conductive materials.

The first electrode 45A is not electrically coupled to the photoelectricconverter 40S. As described above, one side of the first electrode 45Bis electrically coupled to the first contact layer 44, and another sideis electrically coupled to the penetration electrode 47V. One side ofthe penetration electrode 47V is coupled to the first electrode 45B andanother side of the penetration electrode 47V penetrates through theinterlayer insulating film 48A and is coupled to the contact electrode48EB which is electrically coupled to the wiring line 52CB and a contactelectrode 52EB provided in the peripheral region R2 of the circuit board50. For example, in a case where holes are read out from the secondelectrode 41 as signal charges, electrons are discharged through thefirst electrode 45B electrically coupled to the first contact layer 44.Specifically, for example, by applying a positive electric potential tothe first electrode 45A, the concentration of electric charges(specifically, the electron concentration) on the surface (specifically,the first contact layer 44) of the photoelectric converter 40Sincreases, thereby lowering the resistance of the first contact layer44. The electric charges (electrons) extracted via the first contactlayer 44 having a decreased resistance are discharged via the firstelectrode 45B, the penetration electrode 47V, the contact electrodes48EB and 52EB, and the wiring line 52CB, in the peripheral region R2.Thus, by extracting electric charges from the first electrode 45B, it ispossible to reduce the thickness of the first contact layer 44.

The insulating film 46 is provided between the second contact layer 42and the wiring layer 40W, covers an end surface of the second contactlayer 42, an end surface of the photoelectric conversion layer 43, anend surface of the first contact layer 44, and an end surface of the caplayer 15A, and is in contact with the light-shielding film 15B in theperipheral region R2. The insulating film 46 includes, for example, anoxide such as silicon oxide (SiO_(x)), aluminum oxide (Al₂O₃), or thelike. The insulating film 46 may be configured as a stacked structureincluding a plurality of films. The insulating film 46 may include asilicon (Si)-based insulating material such as silicon oxynitride(SiON), carbon-containing silicon oxide (SiOC), silicon nitride (SiN),silicon carbide (SiC), or the like, for example.

The embedded layer 47 fills a step between a temporary substrate (e.g.,the temporary substrate 73) and the photoelectric converter 40S in amanufacturing process of the light receiving element 1.

The embedded layer 47 in the peripheral region R2 is provided betweenthe wiring layer 40W and the insulating layer 49, and has a thicknessmore than or equal to the thickness of the photoelectric converter 40S,for example. Here, since the embedded layer 47 is provided so as tosurround the photoelectric converter 40S, a region (peripheral regionR2) is formed around the photoelectric converter 40S. Thus, it ispossible to provide the bonding surface S2 with the circuit board 50 inthe peripheral region R2. If the bonding surface S2 is formed in theperipheral region R2, the thickness of the embedded layer 47 may bereduced; however, it is preferable that the embedded layer 47 cover thephotoelectric converter 40S over the thickness direction, and that theembedded layer 47 cover the entire surface of the end surface of thephotoelectric converter 40S. By covering the entire end surface of thephotoelectric converter 40S with the embedded layer 47 via theinsulating film 16, it is possible to effectively suppress ingress ofwater into the photoelectric converter 40S.

A surface of the embedded layer 47 on the bonding surface S2 side isflattened, and is provided with the wiring layer 40W on the flattenedsurface of the embedded layer 47 in the peripheral region R2. For theembedded layer 47, for example, it is possible to use an inorganicinsulating material such as silicon oxide (SiO_(X)), silicon nitride(SiN), silicon oxynitride (SiON), carbon-containing silicon oxide(SiOC), silicon carbide (SiC), or the like.

The embedded layer 47 is provided with the penetration electrode 47Vhaving a light-shielding property, for example. The penetrationelectrode 47V electrically couples the first electrode 45B and thewiring line 52CB of the circuit board 50. One side of the penetrationelectrode 47V is coupled to the first electrode 45B. Another side of thepenetration electrode 47V penetrates through the insulating film 46, theembedded layer 47, and the interlayer insulating film 48A, and iscoupled to the contact electrode 48EB provided in the peripheral region.

The support base 51 of the circuit board 50 supports the wiring layer50W and includes, for example, silicon (Si). The wiring layer 50Wincludes, for example, contact electrodes 52EA and 52EB, a pixel circuit52CA, the wiring line 52CB, and a pad electrode 52P, in the interlayerinsulating film 52A. The interlayer insulating film 52A includes aninorganic insulating material, for example. Examples of the inorganicinsulating material include silicon nitride (SiN), aluminum oxide(Al₂O₃), silicon oxide (SiO₂), hafnium oxide (HfO₂), and the like.

The contact electrode 52EA electrically couples the second electrode 41and the pixel circuit 52CA, and is in contact with the contact electrode48EA at the bonding surface S2 of the element substrate 40. Contactelectrodes 52EA adjacent to each other are electrically separated by theinterlayer insulating film 52A.

The contact electrode 52EB electrically couples the first electrode 45and the wiring line 52CB of the circuit board 50, and is in contact withthe contact electrode 48EB at the bonding surface S2 of the elementsubstrate 40. The contact electrode 52EB is formed by the same processas the contact electrode 52EA, for example. The penetration electrode47V may be coupled to the wiring line 52CB without providing the contactelectrodes 48EB and 52EB. The contact electrodes 52EA and 52EB eachinclude, for example, a copper (Cu) pad, and are exposed on a surface,of the circuit board 50, opposing the element substrate 40. That is, aCu—Cu bonding is formed each of between the contact electrode 48EA andthe contact electrode 52EA and between the contact electrode 48EB andthe contact electrode 52EB.

The pixel circuit 52CA is provided for each pixel P, and is coupled tothe contact electrode 52EA. The pixel circuit 52CA includes a ROIC. Thewiring line 52CB coupled to the contact electrode 52EB is coupled to,for example, a predetermined electric potential. In this way, one typeof the electric charges (e.g., holes) generated in the photoelectricconversion layer 43 is read out from the second electrode 41 to thepixel circuit 52CA via the contact electrodes 48EA and 52EA, and theother type of the electric charges (e.g., electrons) generated in thephotoelectric conversion layer 43 is discharged from the first electrode45 to the predetermined electric potential via the penetration electrode47V and the contact electrodes 48EB and 52EB.

The pad electrode 52P electrically couples to the outside. The lightreceiving element 1 is provided with an opening H which penetrates theelement substrate 40 and reaches the pad electrode 52P, and iselectrically coupled to the outside via the opening H. The coupling isachieved by, for example, wire bonding or bumping.

Hereinafter, a method of obtaining the electric potential of theelectrode for discharging electric charges via the first electrode 45and an N-type layer will be described with reference to FIGS. 12A to12C. FIG. 12A schematically illustrates an entire planar configurationof the light receiving element 3A according to the present embodiment.FIG. 12B schematically illustrates a cross-sectional configuration ofthe light receiving element 3A taken along a line I-I illustrated inFIG. 12A. FIG. 12C schematically illustrates a cross-sectionalconfiguration of the light receiving element 3A taken along a line II-IIillustrated in FIG. 12A. In the light receiving element 3A according tothe present embodiment, in the peripheral region R2, a light-shieldingwiring line 47EB electrically coupled to the first electrode 45 isrouted and electrically coupled to the wiring line 52CB provided in thecircuit board 50.

In order to apply different electric potentials to the first electrode45A and the first electrode 45B, it is desirable that the firstelectrode 45A and the first electrode 45B respectively have wiring linesindependent of each other, and are respectively electrically coupled towiring lines 52CB1 and 52CB2, the wiring lines 52CB1 and 52CB2 alsobeing provided independently of each other in the circuit board 50. Inthe present embodiment, as illustrated in FIGS. 12A and 12C, the firstelectrode 45A is electrically coupled (45A-47EB2) to a wiring line 47EB2at the periphery of the pixel region R1 of the peripheral region R2, andis electrically coupled (47EB2-52CB2) to a wiring line 52CB2 providedover the circuit board 50 via a penetration electrode 47V2 and contactelectrodes 48EB2 and 52EB2. As illustrated in FIGS. 12A and 12B, thefirst electrode 45B is electrically coupled (45B-47EB1) to a wiring line47BE1 at the peripheral region R2 outside of the coupling portionbetween the first electrode 45A and the wiring line 47EB2, and iselectrically coupled (47EB1-52CB1) to the wiring line 52CB1 provided ata perimeter portion of the peripheral region R2 over the circuit board50 via a penetration electrode 47V1 and contact electrodes 48EB1 and52EB1, for example. It is to be noted that the routing patterns of therespective wiring lines illustrated in FIGS. 12A to 12C are examples,and the present disclosure is not limited thereto.

3-2. Workings and Effects

It is desired that a semiconductor element (light receiving element) inwhich a photoelectric conversion layer includes a general compoundsemiconductor have a sufficiently increase the thickness of an N-typecompound semiconductor layer, in order to sufficiently reduce theresistance of the N-type compound semiconductor layer formed on thelight incident surface side. However, in a case where the N-typecompound semiconductor layer includes InGaAs, there is an issue that aninfrared absorption coefficient of InGaAs is high, and a resistance asthe electron-extraction wiring line is lowered due to the increase inthickness, but the photoelectric conversion efficiency of infrared lightis lowered.

In contrast, in a case where the N-type compound semiconductor layerincludes InP, the InP layer has a large band gap and an absorption ofthe infrared region is suppressed, so that it is possible to suppressthe reduction in the infrared photoelectric conversion efficiency ascompared to the infrared photoelectric conversion efficiency of theInGaAs layer. Further, the InP layer is also able to suppress generationof a dark current caused by a defective level of an insulating filmformed over a surface of the compound semiconductor layer because of thelarge band gap of the InP layer. However, the InP layer has a highabsorption coefficient to light of the visible light region, and the InPlayer may have a low sensitivity in an image sensor that causes thevisible light to the infrared light to be photoelectrically convertedsimultaneously.

In the present embodiment, the insulating layer 49 is provided on thelight incident surface side of the photoelectric converter 40S in whichthe second contact layer 42, the photoelectric conversion layer 43, andthe first contact layer 14 are stacked in this order toward the lightincident surface, and the first electrode 45 is formed via theinsulating layer 49. It is possible to apply a predetermined voltage tothe first electrode 45, thus, it becomes possible to increase a carrierdensity of the first contact layer 44. Therefore, it is possible toreduce the resistance without increasing the thickness of the firstcontact layer 44.

As described above, in the light receiving element 3A according to thepresent embodiment, the first electrode 45 is formed over thephotoelectric converter 40S via the insulating layer 49. By applying apredetermined voltage to the first electrode 45, the carrierconcentration of the first contact layer 44 is increased and theresistance of the first contact layer 44 is reduced. Therefore, it ispossible to reduce the thickness of the first contact layer 44, and toincrease the sensitivity.

4. Modification Examples 4-1. Modification Example

FIG. 13 schematically illustrates a cross-sectional configuration of alight receiving element (light receiving element 3B) according to apresent modification example (modification example 3) of the presentdisclosure. The light receiving element 3B is applied to, for example,similarly to the light receiving element 3A according to the secondembodiment, an infrared sensor or the like using a compoundsemiconductor material such as a III-V group semiconductor or the like,and has a photoelectric conversion function to light having a wavelengthof a visible region (e.g., more than or equal to 380 nm and less than780 nm) to a short infrared region (e.g., more than or equal to 780 nmand less than 2400 nm), for example. The light receiving element 3Aaccording to the present modification example differs from the secondembodiment in that a light-shielding film 61 electrically coupled to thefirst electrode 45 is provided over the first electrode 45.

The light-shielding film 61 is provided around the pixel region R1 as anoptical black region (OPB region) for determining a signal of a blackreference, is provided between the pixels P adjacent to each other, forexample, and is formed in a lattice shape in a plan view, for example.In addition, the light-shielding film 61 is formed using a conductivematerial; therefore, it is possible to use the light-shielding film 61as a parallel wiring line of the first electrode 45, and to reduce theresistance of the first electrode 45. Further, the light-shielding film61 is formed using a conductive material, and thus making it possible toserve as the penetration electrode 47V according to the secondembodiment (a penetration electrode 61V). As the light-shielding film61, it is possible to use a tungsten (W) film, a copper (Cu) film, analuminum (Al) film, and a silver (Ag) film, or a stacked film thereof.

In the light receiving element 3B according to the present modificationexample, the first electrode 45 in the pixel region R1 includes thefirst electrode 45A that is not electrically coupled to thephotoelectric converter 40S, and the first electrode 45B that iselectrically coupled to the first contact layer 44 of photoelectricconverter 40S, similarly to the second embodiment described above. Inthe first contact layer 44, for example, by a positive electricpotential being applied, an electric charge concentration (specifically,an electron concentration) of a surface (specifically, the first contactlayer 44) of the photoelectric converter 40S is increased and theresistance is reduced. In the similar manner to the second embodiment,the first electrode 45B is electrically coupled to the wiring line 52CBprovided in the circuit board 50 via the penetration electrode 61V andthe contact electrodes 48EB and 52EB. In the similar manner to the firstelectrode 45A, a positive electric potential is applied to the firstelectrode 45B, and electric charges (electrons) extracted via the firstcontact layer 44 in which the resistance is lowered are discharged viathe first electrode 45B. It is to be noted that the first electrode 45Bmay include a metal film included in the light-shielding film 61 inaddition to a transparent conductive material.

As described above, in the present modification example, thelight-shielding film 61 is formed between the pixels P adjacent to eachother over the first electrode 45 in the pixel region R1; therefore, itis possible to suppress generation of crosstalk between the pixels P.Accordingly, in addition to the effects of the second embodiment, it ispossible to achieve the effect that the generation of color mixture isreduced. In addition, the light-shielding film 61 is formed using ametal film; therefore, it is possible to use the light-shielding film 61as a parallel wiring line of the first electrode 45A. This enables theresistance of the first electrode 45 to be lowered.

4-2. Modification Example 4

FIG. 14 schematically illustrates a cross-sectional configuration of alight receiving element (light receiving element 3C) according to apresent modification example (modification example 4) of the presentdisclosure. The light receiving element 3C is applied to, for example,similarly to the light receiving element 3A according to the secondembodiment, an infrared sensor or the like using a compoundsemiconductor material such as a III-V group semiconductor or the like,and has a photoelectric conversion function to light having a wavelengthof a visible region (e.g., more than or equal to 380 nm and less than780 nm) to a short infrared region (e.g., more than or equal to 780 nmand less than 2400 nm), for example. The light receiving element 3Caccording to the present modification example differs from the secondembodiment in that the light-shielding film 61 is provided between theinsulating layer 49 and the first electrode 45.

As described above, the light-shielding film 61 is formed below thefirst electrode 45, and thus enables to shield light at a positioncloser to the photoelectric converter 40S; therefore, it is possible tosuppress generation of crosstalk between the pixels P.

It is to be noted that, in the present modification example, apenetration electrode (a penetration electrode 62V), which isresponsible for electrically coupling the first electrode 45 and thecircuit board 50, is provided separately, and for example, one end ofthe penetration electrode 62V is formed so as to extend over the firstelectrode 45 in the peripheral region R2.

4-3. Modification Example 5

FIG. 15 schematically illustrates a cross-sectional configuration of alight receiving element (modification example 5) according to a presentmodification example (modification example 5) of the present disclosure.The light receiving element 3D is applied to, for example, similarly tothe light receiving element 3A according to the second embodiment, aninfrared sensor or the like using a compound semiconductor material suchas a III-V group semiconductor or the like, and has a photoelectricconversion function to light having a wavelength of a visible region(e.g., more than or equal to 380 nm and less than 780 nm) to a shortinfrared region (e.g., more than or equal to 780 nm and less than 2400nm), for example. The light receiving element 3D according to thepresent modification example differs from the second embodiment in thata carrier-induction film 63, in place of the insulating layer 49, isprovided between the photoelectric converter 40S and the first electrode45.

The carrier-induction film 63 increases a carrier density on a surfaceof the photoelectric converter 40S to decrease the resistance. It isdesirable that the carrier-induction film 63 causes an interface levelwith the photoelectric converter 40S to be reduced, and for example, itis preferable to have a two-layer structure of an interface levelreduction film and a film that promotes carrier induction. For example,in a case where electrons are induced as electric charges, it ispreferable to use a silicon oxide (SiO_(x)) film formed by, for example,an ALD method as the interface level reduction film. Examples of thefilm that promotes carrier induction include an insulating film having apositive fixed electric charge, and for example, a silicon nitride (SiN)film or a silicon oxynitride (SiON) film having a positive (+) electriccharge is preferably used. In a case where holes are induced as electriccharges, it is preferable to use a silicon oxide (SiO_(x)) film formedby, for example, an ALD method as the interface level reduction film.Examples of the film that promotes carrier induction include aninsulating film having a negative fixed electric charge, and forexample, an insulating film containing at least one element selectedfrom hafnium (Hf), zirconium (Zr), aluminum (Al), tantalum (Ta),titanium (Ti), yttrium (Y), and lanthanides is preferably used.

4-4. Modification Example 6

FIG. 16 schematically illustrates a cross-sectional configuration of alight receiving element (light receiving element 3E) according to apresent modification example (modification example 6) of the presentdisclosure. The light receiving element 3E is applied to, for example,similarly to the light receiving element 3A according to the secondembodiment, an infrared sensor or the like using a compoundsemiconductor material such as a III-V group semiconductor or the like,and has a photoelectric conversion function to light having a wavelengthof a visible region (e.g., more than or equal to 380 nm and less than780 nm) to a short infrared region (e.g., more than or equal to 780 nmand less than 2400 nm), for example. The light receiving element 3Eaccording to the present modification example differs from the secondembodiment in that electric charges are discharged via the first contactlayer 44.

The light receiving element 3E according to the present modificationexample has a trench 40X narrowed to the first contact layer 44 side inthe photoelectric converter 40S between the pixel region R1 and theperipheral region R2. Accordingly, in the light receiving element 3E,the holes of the electric charges generated in the photoelectricconversion layer 43 are read out to the pixel circuit 52CA via thecontact electrodes 48EA and 52EA provided in the pixel region R1. Theelectrons are discharged to the wiring line 52CB via the contactelectrodes 48EB and 52EB provided in the peripheral region R2 via anN-type region (the first contact layer 44).

As described above, in the present modification example, the trench 40Xnarrowed to the first contact layer 44 side is provided in thephotoelectric converter 40S between the pixel region R1 and theperipheral region R2; therefore, the contact electrode 48EB iselectrically coupled to the photoelectric converter 40S in the pixelregion R1 via the first contact layer 44. As a result, it is possible touniformly apply, in the pixel region R1, an electric field to the N-typeregion (the first contact layer 44) and a P-type region (a diffusionregion 42A) provided for each pixel.

5. Application Examples Application Example 1

FIG. 17 illustrates a functional configuration of an imaging element 4using an element structure of the light receiving element 1 (or thelight receiving elements 1, 1A, 2, 3A to 3E, hereinafter, collectivelyreferred to as light receiving element 1) described in the foregoingembodiment, etc. The imaging element 4 is, for example, an infraredimage sensor, and includes, for example, a pixel region R1 provided inthe light receiving element 1 and a circuit section 130 that drives thepixel region R1. The circuit section 130 includes, for example, a rowscanner 131, a horizontal selector 133, a column scanner 134, and asystem controller 132.

The pixel region R1 includes, for example, the plurality of pixels P(light receiving element 1) arranged two-dimensionally in matrix. To thepixel P, for example, a pixel driving line Lread (e.g., a row selectionline and a reset control line) is wired for each of pixel rows, and avertical signal line Lsig is wired for each of pixel columns. The pixeldriving line Lread transmits a drive signal for signal readout from thepixel P. One end of the pixel driving line Lread is coupled to an outputend corresponding to each row of the row scanner 131.

The row scanner 131 is a pixel driver that is configured by a shiftregister, an address decoder, etc., and that drives, each of the pixelsP in the pixel region R1 on a row basis, for example. A signal outputtedfrom each of the pixels P of a pixel row selected and scanned by the rowscanner 131 is supplied to the horizontal selector 133 through eachvertical signal line Lsig. The horizontal selector 133 is configured byan amplifier, a horizontal selection switch, etc. provided for eachvertical signal line Lsig.

The column scanner 134 is configured by a shift register, an addressdecoder, etc., and sequentially drives respective horizontal selectionswitches of the horizontal selector 133 while scanning. Signals of therespective pixels transmitted through corresponding vertical signallines Lsig are sequentially outputted to a horizontal signal line 135,through selective scanning by the column scanner 134, and are inputtedto an unillustrated signal processor, etc. through the horizontal signalline 135.

In the imaging element 4, as illustrated in FIG. 18 , for example, anelement substrate 10 including the pixel region R1 and a circuit board20 including a circuit section 130 are stacked. However, the presentdisclosure is not limited to such a configuration, and the circuitsection 130 may be formed on the same substrate as the pixel region R1,or may be disposed on an external control IC. Further, the circuitsection 130 may be formed on another substrate connected by cables orthe like.

The system controller 132 receives a clock provided from outside, datato command an operation mode, etc., and also outputs data such asinternal information on the imaging element 4. The system controller 132further includes a timing generator that generates various timingsignals, and performs driving control of the row scanner 131, thehorizontal selector 133, the column scanner 134, etc., based on thevarious timing signals generated by this timing generator.

Application Example 2

The above-described imaging element 4 is applicable to various kinds ofelectronic apparatuses such as a camera that enables imaging of, forexample, an infrared region. FIG. 19 illustrates a schematicconfiguration of an electronic apparatus 5 (a camera), as an example.This electronic apparatus 5 is, for example, a camera that is able tocapture a still image or a moving image, and includes the imagingelement 4, an optical system (an optical lens) 310, a shutter unit 311,a driver 313 that drives the imaging element 4 and the shutter unit 311,and a signal processor 312.

The optical system 310 guides image light (incident light) from asubject to the imaging element 4. This optical system 310 may beconfigured by a plurality of optical lenses. The shutter unit 311controls a light irradiation period and a light shielding period for theimaging element 4. The driver 313 controls a transfer operation of theimaging element 4 and a shutter operation of the shutter unit 311. Thesignal processor 312 performs various kinds of signal processing, for asignal outputted from the imaging element 4. An image signal Dout afterthe signal processing is stored into a storage medium such as a memory,or outputted to a monitor, etc.

Application Example 3 Example of Application to In-Vivo InformationAcquisition System

Further, the technology (present technology) according to the presentdisclosure is applicable to various products. For example, thetechnology according to the present disclosure may be applied to anendoscopic surgery system.

FIG. 20 is a block diagram depicting an example of a schematicconfiguration of an in-vivo information acquisition system of a patientusing a capsule type endoscope, to which the technology according to anembodiment of the present disclosure (present technology) can beapplied.

The in-vivo information acquisition system 10001 includes a capsule typeendoscope 10100 and an external controlling apparatus 10200.

The capsule type endoscope 10100 is swallowed by a patient at the timeof inspection. The capsule type endoscope 10100 has an image pickupfunction and a wireless communication function and successively picks upan image of the inside of an organ such as the stomach or an intestine(hereinafter referred to as in-vivo image) at predetermined intervalswhile it moves inside of the organ by peristaltic motion for a period oftime until it is naturally discharged from the patient. Then, thecapsule type endoscope 10100 successively transmits information of thein-vivo image to the external controlling apparatus 10200 outside thebody by wireless transmission.

The external controlling apparatus 10200 integrally controls operationof the in-vivo information acquisition system 10001. Further, theexternal controlling apparatus 10200 receives information of an in-vivoimage transmitted thereto from the capsule type endoscope 10100 andgenerates image data for displaying the in-vivo image on a displayapparatus (not depicted) on the basis of the received information of thein-vivo image.

In the in-vivo information acquisition system 10001, an in-vivo imageimaged a state of the inside of the body of a patient can be acquired atany time in this manner for a period of time until the capsule typeendoscope 10100 is discharged after it is swallowed.

A configuration and functions of the capsule type endoscope 10100 andthe external controlling apparatus 10200 are described in more detailbelow.

The capsule type endoscope 10100 includes a housing 10101 of the capsuletype, in which a light source unit 10111, an image pickup unit 10112, animage processing unit 10113, a wireless communication unit 10114, apower feeding unit 10115, a power supply unit 10116 and a control unit10117 are accommodated.

The light source unit 10111 includes a light source such as, forexample, a light emitting diode (LED) and irradiates light on an imagepickup field-of-view of the image pickup unit 10112.

The image pickup unit 10112 includes an image pickup element and anoptical system including a plurality of lenses provided at a precedingstage to the image pickup element. Reflected light (hereinafter referredto as observation light) of light irradiated on a body tissue which isan observation target is condensed by the optical system and introducedinto the image pickup element. In the image pickup unit 10112, theincident observation light is photoelectrically converted by the imagepickup element, by which an image signal corresponding to theobservation light is generated. The image signal generated by the imagepickup unit 10112 is provided to the image processing unit 10113.

The image processing unit 10113 includes a processor such as a centralprocessing unit (CPU) or a graphics processing unit (GPU) and performsvarious signal processes for an image signal generated by the imagepickup unit 10112. The image processing unit 10113 provides the imagesignal for which the signal processes have been performed thereby as RAWdata to the wireless communication unit 10114.

The wireless communication unit 10114 performs a predetermined processsuch as a modulation process for the image signal for which the signalprocesses have been performed by the image processing unit 10113 andtransmits the resulting image signal to the external controllingapparatus 10200 through an antenna 10114A. Further, the wirelesscommunication unit 10114 receives a control signal relating to drivingcontrol of the capsule type endoscope 10100 from the externalcontrolling apparatus 10200 through the antenna 10114A. The wirelesscommunication unit 10114 provides the control signal received from theexternal controlling apparatus 10200 to the control unit 10117.

The power feeding unit 10115 includes an antenna coil for powerreception, a power regeneration circuit for regenerating electric powerfrom current generated in the antenna coil, a voltage booster circuitand so forth. The power feeding unit 10115 generates electric powerusing the principle of non-contact charging.

The power supply unit 10116 includes a secondary battery and storeselectric power generated by the power feeding unit 10115. In FIG. 20 ,in order to avoid complicated illustration, an arrow mark indicative ofa supply destination of electric power from the power supply unit 10116and so forth are omitted. However, electric power stored in the powersupply unit 10116 is supplied to and can be used to drive the lightsource unit 10111, the image pickup unit 10112, the image processingunit 10113, the wireless communication unit 10114 and the control unit10117.

The control unit 10117 includes a processor such as a CPU and suitablycontrols driving of the light source unit 10111, the image pickup unit10112, the image processing unit 10113, the wireless communication unit10114 and the power feeding unit 10115 in accordance with a controlsignal transmitted thereto from the external controlling apparatus10200.

The external controlling apparatus 10200 includes a processor such as aCPU or a GPU, a microcomputer, a control board or the like in which aprocessor and a storage element such as a memory are mixedlyincorporated. The external controlling apparatus 10200 transmits acontrol signal to the control unit 10117 of the capsule type endoscope10100 through an antenna 10200A to control operation of the capsule typeendoscope 10100. In the capsule type endoscope 10100, an irradiationcondition of light upon an observation target of the light source unit10111 can be changed, for example, in accordance with a control signalfrom the external controlling apparatus 10200. Further, an image pickupcondition (for example, a frame rate, an exposure value or the like ofthe image pickup unit 10112) can be changed in accordance with a controlsignal from the external controlling apparatus 10200. Further, thesubstance of processing by the image processing unit 10113 or acondition for transmitting an image signal from the wirelesscommunication unit 10114 (for example, a transmission interval, atransmission image number or the like) may be changed in accordance witha control signal from the external controlling apparatus 10200.

Further, the external controlling apparatus 10200 performs various imageprocesses for an image signal transmitted thereto from the capsule typeendoscope 10100 to generate image data for displaying a picked upin-vivo image on the display apparatus. As the image processes, varioussignal processes can be performed such as, for example, a developmentprocess (demosaic process), an image quality improving process(bandwidth enhancement process, a super-resolution process, a noisereduction (NR) process and/or image stabilization process) and/or anenlargement process (electronic zooming process). The externalcontrolling apparatus 10200 controls driving of the display apparatus tocause the display apparatus to display a picked up in-vivo image on thebasis of generated image data. Alternatively, the external controllingapparatus 10200 may also control a recording apparatus (not depicted) torecord generated image data or control a printing apparatus (notdepicted) to output generated image data by printing.

An example of the in-vivo information acquisition system to which thetechnology according to the present disclosure may be applied has beendescribed above. The technology according to the present disclosure maybe applied, for example, to the image pickup unit 10112 among thecomponents described above. This makes it possible to increase thedetection accuracy.

Application Example 4 4. Example of Application to Endoscopic SurgerySystem

The technology (present technology) according to the present disclosureis applicable to various products. For example, the technology accordingto the present disclosure may be applied to an endoscopic surgerysystem.

FIG. 21 is a view depicting an example of a schematic configuration ofan endoscopic surgery system to which the technology according to anembodiment of the present disclosure (present technology) can beapplied.

In FIG. 21 , a state is illustrated in which a surgeon (medical doctor)11131 is using an endoscopic surgery system 11000 to perform surgery fora patient 11132 on a patient bed 11133. As depicted, the endoscopicsurgery system 11000 includes an endoscope 11100, other surgical tools11110 such as a pneumoperitoneum tube 11111 and an energy device 11112,a supporting arm apparatus 11120 which supports the endoscope 11100thereon, and a cart 11200 on which various apparatus for endoscopicsurgery are mounted.

The endoscope 11100 includes a lens barrel 11101 having a region of apredetermined length from a distal end thereof to be inserted into abody cavity of the patient 11132, and a camera head 11102 connected to aproximal end of the lens barrel 11101. In the example depicted, theendoscope 11100 is depicted which includes as a rigid endoscope havingthe lens barrel 11101 of the hard type. However, the endoscope 11100 mayotherwise be included as a flexible endoscope having the lens barrel11101 of the flexible type.

The lens barrel 11101 has, at a distal end thereof, an opening in whichan objective lens is fitted. A light source apparatus 11203 is connectedto the endoscope 11100 such that light generated by the light sourceapparatus 11203 is introduced to a distal end of the lens barrel 11101by a light guide extending in the inside of the lens barrel 11101 and isirradiated toward an observation target in a body cavity of the patient11132 through the objective lens. It is to be noted that the endoscope11100 may be a forward-viewing endoscope or may be an oblique-viewingendoscope or a side-viewing endoscope.

An optical system and an image pickup element are provided in the insideof the camera head 11102 such that reflected light (observation light)from the observation target is condensed on the image pickup element bythe optical system. The observation light is photo-electricallyconverted by the image pickup element to generate an electric signalcorresponding to the observation light, namely, an image signalcorresponding to an observation image. The image signal is transmittedas RAW data to a CCU 11201.

The CCU 11201 includes a central processing unit (CPU), a graphicsprocessing unit (GPU) or the like and integrally controls operation ofthe endoscope 11100 and a display apparatus 11202. Further, the CCU11201 receives an image signal from the camera head 11102 and performs,for the image signal, various image processes for displaying an imagebased on the image signal such as, for example, a development process(demosaic process).

The display apparatus 11202 displays thereon an image based on an imagesignal, for which the image processes have been performed by the CCU11201, under the control of the CCU 11201.

The light source apparatus 11203 includes a light source such as, forexample, a light emitting diode (LED) and supplies irradiation lightupon imaging of a surgical region to the endoscope 11100.

An inputting apparatus 11204 is an input interface for the endoscopicsurgery system 11000. A user can perform inputting of various kinds ofinformation or instruction inputting to the endoscopic surgery system11000 through the inputting apparatus 11204. For example, the user wouldinput an instruction or a like to change an image pickup condition (typeof irradiation light, magnification, focal distance or the like) by theendoscope 11100.

A treatment tool controlling apparatus 11205 controls driving of theenergy device 11112 for cautery or incision of a tissue, sealing of ablood vessel or the like. A pneumoperitoneum apparatus 11206 feeds gasinto a body cavity of the patient 11132 through the pneumoperitoneumtube 11111 to inflate the body cavity in order to secure the field ofview of the endoscope 11100 and secure the working space for thesurgeon. A recorder 11207 is an apparatus capable of recording variouskinds of information relating to surgery. A printer 11208 is anapparatus capable of printing various kinds of information relating tosurgery in various forms such as a text, an image or a graph.

It is to be noted that the light source apparatus 11203 which suppliesirradiation light when a surgical region is to be imaged to theendoscope 11100 may include a white light source which includes, forexample, an LED, a laser light source or a combination of them. Where awhite light source includes a combination of red, green, and blue (RGB)laser light sources, since the output intensity and the output timingcan be controlled with a high degree of accuracy for each color (eachwavelength), adjustment of the white balance of a picked up image can beperformed by the light source apparatus 11203. Further, in this case, iflaser beams from the respective RGB laser light sources are irradiatedtime-divisionally on an observation target and driving of the imagepickup elements of the camera head 11102 are controlled in synchronismwith the irradiation timings. Then images individually corresponding tothe R, G and B colors can be also picked up time-divisionally. Accordingto this method, a color image can be obtained even if color filters arenot provided for the image pickup element.

Further, the light source apparatus 11203 may be controlled such thatthe intensity of light to be outputted is changed for each predeterminedtime. By controlling driving of the image pickup element of the camerahead 11102 in synchronism with the timing of the change of the intensityof light to acquire images time-divisionally and synthesizing theimages, an image of a high dynamic range free from underexposed blockedup shadows and overexposed highlights can be created.

Further, the light source apparatus 11203 may be configured to supplylight of a predetermined wavelength band ready for special lightobservation. In special light observation, for example, by utilizing thewavelength dependency of absorption of light in a body tissue toirradiate light of a narrow band in comparison with irradiation lightupon ordinary observation (namely, white light), narrow band observation(narrow band imaging) of imaging a predetermined tissue such as a bloodvessel of a superficial portion of the mucous membrane or the like in ahigh contrast is performed. Alternatively, in special light observation,fluorescent observation for obtaining an image from fluorescent lightgenerated by irradiation of excitation light may be performed. Influorescent observation, it is possible to perform observation offluorescent light from a body tissue by irradiating excitation light onthe body tissue (autofluorescence observation) or to obtain afluorescent light image by locally injecting a reagent such asindocyanine green (ICG) into a body tissue and irradiating excitationlight corresponding to a fluorescent light wavelength of the reagentupon the body tissue. The light source apparatus 11203 can be configuredto supply such narrow-band light and/or excitation light suitable forspecial light observation as described above.

FIG. 22 is a block diagram depicting an example of a functionalconfiguration of the camera head 11102 and the CCU 11201 depicted inFIG. 21 .

The camera head 11102 includes a lens unit 11401, an image pickup unit11402, a driving unit 11403, a communication unit 11404 and a camerahead controlling unit 11405. The CCU 11201 includes a communication unit11411, an image processing unit 11412 and a control unit 11413. Thecamera head 11102 and the CCU 11201 are connected for communication toeach other by a transmission cable 11400.

The lens unit 11401 is an optical system, provided at a connectinglocation to the lens barrel 11101. Observation light taken in from adistal end of the lens barrel 11101 is guided to the camera head 11102and introduced into the lens unit 11401. The lens unit 11401 includes acombination of a plurality of lenses including a zoom lens and afocusing lens.

The number of image pickup elements which is included by the imagepickup unit 11402 may be one (single-plate type) or a plural number(multi-plate type). Where the image pickup unit 11402 is configured asthat of the multi-plate type, for example, image signals correspondingto respective R, G and B are generated by the image pickup elements, andthe image signals may be synthesized to obtain a color image. The imagepickup unit 11402 may also be configured so as to have a pair of imagepickup elements for acquiring respective image signals for the right eyeand the left eye ready for three dimensional (3D) display. If 3D displayis performed, then the depth of a living body tissue in a surgicalregion can be comprehended more accurately by the surgeon 11131. It isto be noted that, where the image pickup unit 11402 is configured asthat of stereoscopic type, a plurality of systems of lens units 11401are provided corresponding to the individual image pickup elements.

Further, the image pickup unit 11402 may not necessarily be provided onthe camera head 11102. For example, the image pickup unit 11402 may beprovided immediately behind the objective lens in the inside of the lensbarrel 11101.

The driving unit 11403 includes an actuator and moves the zoom lens andthe focusing lens of the lens unit 11401 by a predetermined distancealong an optical axis under the control of the camera head controllingunit 11405. Consequently, the magnification and the focal point of apicked up image by the image pickup unit 11402 can be adjusted suitably.

The communication unit 11404 includes a communication apparatus fortransmitting and receiving various kinds of information to and from theCCU 11201. The communication unit 11404 transmits an image signalacquired from the image pickup unit 11402 as RAW data to the CCU 11201through the transmission cable 11400.

In addition, the communication unit 11404 receives a control signal forcontrolling driving of the camera head 11102 from the CCU 11201 andsupplies the control signal to the camera head controlling unit 11405.The control signal includes information relating to image pickupconditions such as, for example, information that a frame rate of apicked up image is designated, information that an exposure value uponimage picking up is designated and/or information that a magnificationand a focal point of a picked up image are designated.

It is to be noted that the image pickup conditions such as the framerate, exposure value, magnification or focal point may be designated bythe user or may be set automatically by the control unit 11413 of theCCU 11201 on the basis of an acquired image signal. In the latter case,an auto exposure (AE) function, an auto focus (AF) function and an autowhite balance (AWB) function are incorporated in the endoscope 11100.

The camera head controlling unit 11405 controls driving of the camerahead 11102 on the basis of a control signal from the CCU 11201 receivedthrough the communication unit 11404.

The communication unit 11411 includes a communication apparatus fortransmitting and receiving various kinds of information to and from thecamera head 11102. The communication unit 11411 receives an image signaltransmitted thereto from the camera head 11102 through the transmissioncable 11400.

Further, the communication unit 11411 transmits a control signal forcontrolling driving of the camera head 11102 to the camera head 11102.The image signal and the control signal can be transmitted by electricalcommunication, optical communication or the like.

The image processing unit 11412 performs various image processes for animage signal in the form of RAW data transmitted thereto from the camerahead 11102.

The control unit 11413 performs various kinds of control relating toimage picking up of a surgical region or the like by the endoscope 11100and display of a picked up image obtained by image picking up of thesurgical region or the like. For example, the control unit 11413 createsa control signal for controlling driving of the camera head 11102.

Further, the control unit 11413 controls, on the basis of an imagesignal for which image processes have been performed by the imageprocessing unit 11412, the display apparatus 11202 to display a pickedup image in which the surgical region or the like is imaged. Thereupon,the control unit 11413 may recognize various objects in the picked upimage using various image recognition technologies. For example, thecontrol unit 11413 can recognize a surgical tool such as forceps, aparticular living body region, bleeding, mist when the energy device11112 is used and so forth by detecting the shape, color and so forth ofedges of objects included in a picked up image. The control unit 11413may cause, when it controls the display apparatus 11202 to display apicked up image, various kinds of surgery supporting information to bedisplayed in an overlapping manner with an image of the surgical regionusing a result of the recognition. Where surgery supporting informationis displayed in an overlapping manner and presented to the surgeon11131, the burden on the surgeon 11131 can be reduced and the surgeon11131 can proceed with the surgery with certainty.

The transmission cable 11400 which connects the camera head 11102 andthe CCU 11201 to each other is an electric signal cable ready forcommunication of an electric signal, an optical fiber ready for opticalcommunication or a composite cable ready for both of electrical andoptical communications.

Here, while, in the example depicted, communication is performed bywired communication using the transmission cable 11400, thecommunication between the camera head 11102 and the CCU 11201 may beperformed by wireless communication.

An example of the endoscopic surgery system to which the technologyaccording to the present disclosure may be applied has been describedabove. The technology according to the present disclosure may be appliedto the image pickup unit 11402 among the components described above.Applying the technology according to an embodiment of the presentdisclosure to the image pickup unit 11402 increases the detectionaccuracy.

It is to be noted that the endoscopic surgery system has been describedhere as an example, but the technology according to the presentdisclosure may be additionally applied to, for example, a microscopicsurgery system or the like.

Application Example 5 Example of Application to Mobile Body

The technology according to the present disclosure is applicable tovarious products. For example, the technology according to the presentdisclosure may be achieved as a device mounted on any type of mobilebody such as a vehicle, an electric vehicle, a hybrid electric vehicle,a motorcycle, a bicycle, a personal mobility, an airplane, a drone, avessel, a robot, a construction machine, or an agricultural machine(tractor).

FIG. 23 is a block diagram depicting an example of schematicconfiguration of a vehicle control system as an example of a mobile bodycontrol system to which the technology according to an embodiment of thepresent disclosure can be applied.

The vehicle control system 12000 includes a plurality of electroniccontrol units connected to each other via a communication network 12001.In the example depicted in FIG. 23 , the vehicle control system 12000includes a driving system control unit 12010, a body system control unit12020, an outside-vehicle information detecting unit 12030, anin-vehicle information detecting unit 12040, and an integrated controlunit 12050. In addition, a microcomputer 12051, a sound/image outputsection 12052, and a vehicle-mounted network interface (I/F) 12053 areillustrated as a functional configuration of the integrated control unit12050.

The driving system control unit 12010 controls the operation of devicesrelated to the driving system of the vehicle in accordance with variouskinds of programs. For example, the driving system control unit 12010functions as a control device for a driving force generating device forgenerating the driving force of the vehicle, such as an internalcombustion engine, a driving motor, or the like, a driving forcetransmitting mechanism for transmitting the driving force to wheels, asteering mechanism for adjusting the steering angle of the vehicle, abraking device for generating the braking force of the vehicle, and thelike.

The body system control unit 12020 controls the operation of variouskinds of devices provided to a vehicle body in accordance with variouskinds of programs. For example, the body system control unit 12020functions as a control device for a keyless entry system, a smart keysystem, a power window device, or various kinds of lamps such as aheadlamp, a backup lamp, a brake lamp, a turn signal, a fog lamp, or thelike. In this case, radio waves transmitted from a mobile device as analternative to a key or signals of various kinds of switches can beinput to the body system control unit 12020. The body system controlunit 12020 receives these input radio waves or signals, and controls adoor lock device, the power window device, the lamps, or the like of thevehicle.

The outside-vehicle information detecting unit 12030 detects informationabout the outside of the vehicle including the vehicle control system12000. For example, the outside-vehicle information detecting unit 12030is connected with an imaging section 12031. The outside-vehicleinformation detecting unit 12030 makes the imaging section 12031 imagean image of the outside of the vehicle, and receives the imaged image.On the basis of the received image, the outside-vehicle informationdetecting unit 12030 may perform processing of detecting an object suchas a human, a vehicle, an obstacle, a sign, a character on a roadsurface, or the like, or processing of detecting a distance thereto.

The imaging section 12031 is an optical sensor that receives light, andwhich outputs an electric signal corresponding to a received lightamount of the light. The imaging section 12031 can output the electricsignal as an image, or can output the electric signal as informationabout a measured distance. In addition, the light received by theimaging section 12031 may be visible light, or may be invisible lightsuch as infrared rays or the like.

The in-vehicle information detecting unit 12040 detects informationabout the inside of the vehicle. The in-vehicle information detectingunit 12040 is, for example, connected with a driver state detectingsection 12041 that detects the state of a driver. The driver statedetecting section 12041, for example, includes a camera that images thedriver. On the basis of detection information input from the driverstate detecting section 12041, the in-vehicle information detecting unit12040 may calculate a degree of fatigue of the driver or a degree ofconcentration of the driver, or may determine whether the driver isdozing.

The microcomputer 12051 can calculate a control target value for thedriving force generating device, the steering mechanism, or the brakingdevice on the basis of the information about the inside or outside ofthe vehicle which information is obtained by the outside-vehicleinformation detecting unit 12030 or the in-vehicle information detectingunit 12040, and output a control command to the driving system controlunit 12010. For example, the microcomputer 12051 can perform cooperativecontrol intended to implement functions of an advanced driver assistancesystem (ADAS) which functions include collision avoidance or shockmitigation for the vehicle, following driving based on a followingdistance, vehicle speed maintaining driving, a warning of collision ofthe vehicle, a warning of deviation of the vehicle from a lane, or thelike.

In addition, the microcomputer 12051 can perform cooperative controlintended for automatic driving, which makes the vehicle to travelautonomously without depending on the operation of the driver, or thelike, by controlling the driving force generating device, the steeringmechanism, the braking device, or the like on the basis of theinformation about the outside or inside of the vehicle which informationis obtained by the outside-vehicle information detecting unit 12030 orthe in-vehicle information detecting unit 12040.

In addition, the microcomputer 12051 can output a control command to thebody system control unit 12020 on the basis of the information about theoutside of the vehicle which information is obtained by theoutside-vehicle information detecting unit 12030. For example, themicrocomputer 12051 can perform cooperative control intended to preventa glare by controlling the headlamp so as to change from a high beam toa low beam, for example, in accordance with the position of a precedingvehicle or an oncoming vehicle detected by the outside-vehicleinformation detecting unit 12030.

The sound/image output section 12052 transmits an output signal of atleast one of a sound and an image to an output device capable ofvisually or auditorily notifying information to an occupant of thevehicle or the outside of the vehicle. In the example of FIG. 23 , anaudio speaker 12061, a display section 12062, and an instrument panel12063 are illustrated as the output device. The display section 12062may, for example, include at least one of an on-board display and ahead-up display.

FIG. 24 is a diagram depicting an example of the installation positionof the imaging section 12031.

In FIG. 24 , the imaging section 12031 includes imaging sections 12101,12102, 12103, 12104, and 12105.

The imaging sections 12101, 12102, 12103, 12104, and 12105 are, forexample, disposed at positions on a front nose, sideview mirrors, a rearbumper, and a back door of the vehicle 12100 as well as a position on anupper portion of a windshield within the interior of the vehicle. Theimaging section 12101 provided to the front nose and the imaging section12105 provided to the upper portion of the windshield within theinterior of the vehicle obtain mainly an image of the front of thevehicle 12100. The imaging sections 12102 and 12103 provided to thesideview mirrors obtain mainly an image of the sides of the vehicle12100. The imaging section 12104 provided to the rear bumper or the backdoor obtains mainly an image of the rear of the vehicle 12100. Theimaging section 12105 provided to the upper portion of the windshieldwithin the interior of the vehicle is used mainly to detect a precedingvehicle, a pedestrian, an obstacle, a signal, a traffic sign, a lane, orthe like.

Incidentally, FIG. 24 depicts an example of photographing ranges of theimaging sections 12101 to 12104. An imaging range 12111 represents theimaging range of the imaging section 12101 provided to the front nose.Imaging ranges 12112 and 12113 respectively represent the imaging rangesof the imaging sections 12102 and 12103 provided to the sideviewmirrors. An imaging range 12114 represents the imaging range of theimaging section 12104 provided to the rear bumper or the back door. Abird's-eye image of the vehicle 12100 as viewed from above is obtainedby superimposing image data imaged by the imaging sections 12101 to12104, for example.

At least one of the imaging sections 12101 to 12104 may have a functionof obtaining distance information. For example, at least one of theimaging sections 12101 to 12104 may be a stereo camera constituted of aplurality of imaging elements, or may be an imaging element havingpixels for phase difference detection.

For example, the microcomputer 12051 can determine a distance to eachthree-dimensional object within the imaging ranges 12111 to 12114 and atemporal change in the distance (relative speed with respect to thevehicle 12100) on the basis of the distance information obtained fromthe imaging sections 12101 to 12104, and thereby extract, as a precedingvehicle, a nearest three-dimensional object in particular that ispresent on a traveling path of the vehicle 12100 and which travels insubstantially the same direction as the vehicle 12100 at a predeterminedspeed (for example, equal to or more than 0 km/hour). Further, themicrocomputer 12051 can set a following distance to be maintained infront of a preceding vehicle in advance, and perform automatic brakecontrol (including following stop control), automatic accelerationcontrol (including following start control), or the like. It is thuspossible to perform cooperative control intended for automatic drivingthat makes the vehicle travel autonomously without depending on theoperation of the driver or the like.

For example, the microcomputer 12051 can classify three-dimensionalobject data on three-dimensional objects into three-dimensional objectdata of a two-wheeled vehicle, a standard-sized vehicle, a large-sizedvehicle, a pedestrian, a utility pole, and other three-dimensionalobjects on the basis of the distance information obtained from theimaging sections 12101 to 12104, extract the classifiedthree-dimensional object data, and use the extracted three-dimensionalobject data for automatic avoidance of an obstacle. For example, themicrocomputer 12051 identifies obstacles around the vehicle 12100 asobstacles that the driver of the vehicle 12100 can recognize visuallyand obstacles that are difficult for the driver of the vehicle 12100 torecognize visually. Then, the microcomputer 12051 determines a collisionrisk indicating a risk of collision with each obstacle. In a situationin which the collision risk is equal to or higher than a set value andthere is thus a possibility of collision, the microcomputer 12051outputs a warning to the driver via the audio speaker 12061 or thedisplay section 12062, and performs forced deceleration or avoidancesteering via the driving system control unit 12010. The microcomputer12051 can thereby assist in driving to avoid collision.

At least one of the imaging sections 12101 to 12104 may be an infraredcamera that detects infrared rays. The microcomputer 12051 can, forexample, recognize a pedestrian by determining whether or not there is apedestrian in imaged images of the imaging sections 12101 to 12104. Suchrecognition of a pedestrian is, for example, performed by a procedure ofextracting characteristic points in the imaged images of the imagingsections 12101 to 12104 as infrared cameras and a procedure ofdetermining whether or not it is the pedestrian by performing patternmatching processing on a series of characteristic points representingthe contour of the object. When the microcomputer 12051 determines thatthere is a pedestrian in the imaged images of the imaging sections 12101to 12104, and thus recognizes the pedestrian, the sound/image outputsection 12052 controls the display section 12062 so that a squarecontour line for emphasis is displayed so as to be superimposed on therecognized pedestrian. The sound/image output section 12052 may alsocontrol the display section 12062 so that an icon or the likerepresenting the pedestrian is displayed at a desired position.

Although the first and second embodiments, the modification examples 1to 6, and the application examples have been described above, thepresent disclosure is not limited to the above-described embodiments andthe like, and various modifications can be made. For example, the layerstructures of the light receiving elements described in the aboveembodiments are examples, and other layers may be further provided. Thematerials and thicknesses of the respective layers are also examples andare not limited to those described above. For example, in theembodiments and the like described above, the case in which thephotoelectric converter 10S includes the second contact layer 12, thephotoelectric conversion layer 13, and the first contact layer 14;however, the photoelectric converter 10S only has to include thephotoelectric conversion layer 13. For example, the second contact layer12 and the first contact layer 14 may not necessarily be provided, orother layers may be included.

Further, in the embodiments and the like described above, forconvenience, the case in which the signal charge is a hole; however, thesignal charge may be an electron. For example, the diffusion region mayinclude an n-type impurity. Further, the modification examples 1 to 6described above may be used in combination with each other.

In addition, in the embodiments and the like described above, the lightreceiving element of one specific example of the semiconductor elementaccording to the present technology has been described; however, thesemiconductor element according to the present technology may be otherthan the light receiving element. For example, the semiconductor elementaccording to the present technology may be a light emitting element.

In addition, the effects described in the above embodiments and the likedescribed above are merely examples, and other effects may be achieved,or other effects may be further included.

It is to be noted that the present disclosure may have the followingconfigurations.

(1)

-   -   A light receiving element including:    -   a plurality of pixels;    -   a photoelectric converter that is provided as a layer common to        the plurality of pixels, and contains a compound semiconductor        material; and a first electrode layer that is provided between        the plurality of pixels on light incident surface side of the        photoelectric converter, and has a light-shielding property.        (2)    -   The light receiving element according to (1), in which the first        electrode layer includes a metal film having a light-shielding        property.        (3)    -   The light receiving element according to (1) or (2), in which        the first electrode layer has a stacked structure including a        first semiconductor layer and a metal film, the metal film        having a light-shielding property.        (4)    -   The light receiving element according to any one of (1) to (3),        in which the first electrode layer has a lattice shape.        (5)    -   The light receiving element according to any one of (1) to (4),        in which the photoelectric converter includes a photoelectric        conversion layer, a first contact layer provided between the        photoelectric conversion layer and the first electrode layer,        and a second contact layer provided on side, of the        photoelectric conversion layer, opposite to the first contact        layer.        (6)    -   The light receiving element according to (5), in which the        second contact layer includes a first conduction-type region        provided in a region that opposes each of the plurality of        pixels, and a second conduction-type region around the first        conduction-type region.        (7)    -   The light receiving element according to any one of (1) to (6),        in which    -   the light receiving element includes a pixel region in which the        plurality of pixels is provided and a peripheral region provided        outside the pixel region, and the first electrode layer is        electrically coupled, at a perimeter of the pixel region, to a        readout electrode provided in the peripheral region.        (8)    -   The light receiving element according to any one of (5) to (7),        in which the photoelectric conversion layer absorbs a wavelength        in at least an infrared region and generates electric charges.        (9)    -   The light receiving element according to any one of (3) to (8),        in which a photoelectric conversion layer, a first contact        layer, and a second contact layer that use the photoelectric        converter, and the first semiconductor layer each include a        III-V group semiconductor material.        (10)    -   The light receiving element according to (9), in which    -   the photoelectric conversion layer and the first semiconductor        layer each include InGaAs, and    -   the first contact layer and the second contact layer each        include InP or InGaAs.        (11)    -   A light receiving element including:    -   a plurality of pixels;    -   a photoelectric converter that includes a compound semiconductor        material, is provided as a layer common to the plurality of        pixels, and has a stacked structure in which a photoelectric        conversion layer, a first contact layer, and a second contact        layer are stacked, the photoelectric conversion layer being        provided between the first contact layer and the second contact        layer;    -   an insulating layer provided over the photoelectric converter;        and    -   a transparent electrode layer provided over the insulating        layer.        (12)    -   The light receiving element according to (11), further including        a light-shielding film between the insulating layer and the        transparent electrode layer or between the plurality of pixels        provided over the transparent electrode layer.        (13)    -   The light receiving element according to (11) or (12), in which        the insulating layer includes a carrier-induction film.        (14)    -   The light receiving element according to any one of (11) to        (13), in which    -   the first contact layer is provided over light incident surface        side of the photoelectric conversion layer, and has one        conduction type, and    -   the second contact layer is provided on side, of the        photoelectric conversion layer, opposite to the light incident        surface, and has, inside a layer having one conduction type, a        region of another conduction type for each of the pixels.        (15)    -   An electronic apparatus including    -   a light receiving element, the light receiving element including        -   a plurality of pixels,        -   a photoelectric converter that is provided as a layer common            to the plurality of pixels, and contains a compound            semiconductor material, and        -   a first electrode layer that is provided between the            plurality of pixels on light incident surface side of the            photoelectric converter, and has a light-shielding property.            (16)    -   An electronic apparatus including    -   a light receiving element, the light receiving element including        -   a plurality of pixels,        -   a photoelectric converter that includes a compound            semiconductor material, is provided as a layer common to the            plurality of pixels, and has a stacked structure in which a            photoelectric conversion layer, a first contact layer, and a            second contact layer are stacked, the photoelectric            conversion layer being provided between the first contact            layer and the second contact layer,        -   an insulating layer provided over the photoelectric            converter, and        -   a transparent electrode layer provided over the insulating            layer.

This application claims the benefit of Japanese Priority PatentApplication JP2017-253637 filed with the Japan Patent Office on Dec. 28,2017, the entire contents of which are incorporated herein by reference.

It should be understood by those skilled in the art that variousmodifications, combinations, sub-combinations, and alterations may occurdepending on design requirements and other factors insofar as they arewithin the scope of the appended claims or the equivalents thereof

The invention claimed is:
 1. A light receiving element, comprising: aplurality of pixels; a photoelectric converter that includes a compoundsemiconductor material, is provided as a layer common to the pluralityof pixels, and has a stacked structure in which a photoelectricconversion layer, a first contact layer, and a second contact layer arestacked, the photoelectric conversion layer being provided between thefirst contact layer and the second contact layer; an insulating layerprovided over the photoelectric converter; and a transparent electrodelayer provided over the insulating layer, wherein the insulating layerincludes a carrier-induction film.
 2. The light receiving elementaccording to claim 1, wherein the light receiving element includes apixel region in which the plurality of pixels is provided and aperipheral region provided outside the pixel region, and wherein a firstelectrode layer is electrically coupled, at a perimeter of the pixelregion, to a readout electrode provided in the peripheral region.
 3. Thelight receiving element according to claim 1, wherein the photoelectricconversion layer absorbs a wavelength in at least an infrared region andgenerates electric charges.
 4. The light receiving element according toclaim 1, wherein the photoelectric conversion layer includes InGaAs, andwherein the first contact layer includes InP.
 5. The light receivingelement according to claim 1, further comprising a light-shielding filmbetween the insulating layer and the transparent electrode layer orbetween the plurality of pixels provided over the transparent electrodelayer.
 6. The light receiving element according to claim 1, wherein thefirst contact layer is provided over a light incident surface side ofthe photoelectric conversion layer, and has one conduction type, andwherein the second contact layer is provided on a side of thephotoelectric conversion layer opposite to the light incident surface,and has, inside a layer having one conduction type, a region of anotherconduction type for each of the pixels.
 7. The light receiving elementaccording to claim 1, wherein the photoelectric conversion layer, thefirst contact layer and the second contact layer each includes a III-Vgroup semiconductor material.
 8. An electronic apparatus, comprising: alight receiving element, the light receiving element including: aplurality of pixels, a photoelectric converter that includes a compoundsemiconductor material, is provided as a layer common to the pluralityof pixels, and has a stacked structure in which a photoelectricconversion layer, a first contact layer, and a second contact layer arestacked, the photoelectric conversion layer being provided between thefirst contact layer and the second contact layer, an insulating layerprovided over the photoelectric converter, and a transparent electrodelayer provided over the insulating layer, wherein the insulating layerincludes a carrier-induction film.
 9. The electronic apparatus accordingto claim 8, further comprising a light-shielding film between theinsulating layer and the transparent electrode layer or between theplurality of pixels provided over the transparent electrode layer. 10.The electronic apparatus according to claim 8, wherein the first contactlayer is provided over a light incident surface side of thephotoelectric conversion layer, and has one conduction type, and whereinthe second contact layer is provided on a side of the photoelectricconversion layer opposite to the light incident surface, and has, insidea layer having one conduction type, a region of another conduction typefor each of the pixels.
 11. The electronic apparatus according to claim8, wherein the photoelectric conversion layer absorbs a wavelength in atleast an infrared region and generates electric charges.
 12. Theelectronic apparatus according to claim 8, wherein the photoelectricconversion layer includes InGaAs, and wherein the first contact layerincludes InP.
 13. The electronic apparatus according to claim 8, whereinthe photoelectric conversion layer, the first contact layer and thesecond contact layer each includes a III-V group semiconductor material.